LBNL Physics Division Research Progress Meetings

Speaker: Ryan Gibbons (UC Berkeley) - Title: Searching for Dark Matter with LZ and Future LZ Upgrades
2024-12-19 16:00 - 17:00 UTC
Research Progress Meeting
Date: December 19, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Ryan Gibbons (UC Berkeley)
Title: Searching for Dark Matter with LZ and Future LZ Upgrades
Abstract: Direct detection of particle dark matter remains an outstanding opportunity in understanding the nature of the universe, and for discovery of physics beyond the Standard Model. I will discuss the LUX-ZEPLIN (LZ) experiment’s world-leading WIMP dark matter searches as well as a novel search for neutrinoless double beta decay. In addition, I will present three avenues of instrumentation work at LBNL for potential upgrades to the LZ experiment: a solid xenon TPC (crystaLiZe), light element doping of xenon (HydroX), and mitigation of instrument backgrounds to enable sub-GeV dark matter searches.
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Meeting ID: 988 5432 2464

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Speaker: Lloyd Knox (UC Davis) - Title: A Polarized Look at the Hubble Constant Problem
2025-01-16 16:00 - 17:00
Research Progress Meeting
Date: January 16, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Lloyd Knox (UC Davis)
Title: A Polarized Look at the Hubble Constant Problem
Abstract: The standard cosmological model has met with enormous empirical success over the past two decades. Continued testing of the model is highly warranted as it relies on additional components beyond the standard model of particle physics: the cold dark matter, the cosmological constant, and some mechanism for generating initial density perturbations. Additional motivation comes from a number of empirical suggestions of deficiencies in the model, with the most statistically significant among these a mismatch between different methods for determining the current rate of the expansion of space (the Hubble constant). In this talk I will present our use of cosmic microwave background (CMB) polarization data from the third generation camera on the South Pole Telescope (SPT-3G) to provide stringent tests of the standard cosmological model and determine the Hubble constant with a standard error of 1.2% using CMB polarization data alone.
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Meeting ID: 988 5432 2464

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Speaker: Nicole Yunger Halpern (NIST + QuICS + University of Maryland) - Title: Quantum thermodynamics for lattice gauge theories
2025-01-23 16:00 - 17:00
Research Progress Meeting
Date: January 23, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Nicole Yunger Halpern (NIST + QuICS + University of Maryland)
Title: Quantum thermodynamics for lattice gauge theories
Abstract: A key objective in nuclear and high-energy physics is to describe nonequilibrium dynamics of matter, e.g., in the early universe and in particle colliders, starting from the Standard Model. Classical-computing methods, via the framework of lattice gauge theory, have experienced limited success in this mission. Quantum simulation of lattice gauge theories holds promise for overcoming computational limitations. Because of local constraints (Gauss’s laws), lattice gauge theories have an intricate Hilbert-space structure. This structure complicates the definition of thermodynamic properties of systems coupled to reservoirs during equilibrium and nonequilibrium processes. We show how to define thermodynamic quantities such as work and heat using strong-coupling thermodynamics, a framework that has recently burgeoned within the field of quantum thermodynamics. Our definitions suit instantaneous quenches, simple nonequilibrium processes undertaken in quantum simulators. To illustrate our framework, we compute the work and heat exchanged during a quench in a Z2 lattice gauge theory coupled to matter in 1+1 dimensions. The thermodynamic quantities, as functions of the quench parameter, evidence an expected phase transition.
Reference: Davoudi, Jarzynski, Mueller, Oruganti, Powers, and NYH, Phys. Rev. Lett. 133, 250402 (2024). https://journals.aps.org/prl/abstract/10.1103/ PhysRevLett.133.250402
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Speaker: Krishna Rajagopal (MIT) - Title: Novel Probes of the Primordial Liquid
2025-02-13 16:00 - 17:00
Research Progress Meeting
Date: February 13, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Krishna Rajagopal (MIT)
Title: Novel Probes of the Primordial Liquid
Abstract: Heavy ion collisions reproduce droplets of the trillions-of-degrees-hot liquid that filled the microseconds-old universe, conventionally called quark-gluon plasma (QGP) but better thought of as hot quark soup. Over the past twenty years, data obtained via recreating this primordial fluid have shown that it is the most liquid liquid in the universe, making it the first complex matter to form as well as the source of all protons and neutrons. After a look at what we have learned about the formation and properties of this original liquid from heavy ion collisions, I will focus on the road ahead, in particular on new probes being developed to answer questions like: How does a strongly coupled liquid emerge, given that what you will see if you can probe QGP with high resolution is weakly coupled quarks and gluons? How can we use jets to see the inner workings of QGP and answer this question? And how does the droplet of QGP ripple after it has been probed by a passing jet?
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Speaker: Aishik Ghosh (UCI), Title: Overcoming challenges of quantum interference in Higgs physics with high-dimensional statistics
2025-02-20 16:00 - 17:00 | 50A-5132 Sessler-Join Zoom
Abstract: Quantum interference between signal and background Feynman diagrams produce non-linear effects that challenge core assumptions going into the statistical analysis methodology in particle physics. I show that for such cases, no single observable can capture all the relevant information needed to perform optimal inference of theory parameters from data collected in our experiments. The optimal data analysis strategy is to perform statistical inference directly on high-dimensional data, without relying on summary histograms. Neural Simulation-Based Inference (NSBI) is a class of techniques that naturally handle high dimensional data, avoiding the need to design low-dimensional summary histograms. We design a general purpose statistical framework in the ATLAS experiment that enables the application of NSBI to full-scale physics analyses, leading to a second publication of the Higgs width measurement on Run2 data, significantly outperforming the previous measurement punished by the experiment on the same data.
Tea and cookies will be served from 3:45 – 4:00 pm in the Sessler conference room.
If you’d like to meet with the speaker, please send your request to Liz Worthy.
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Speaker: Atsushi J. Nishizawa (Gifu Shotoku Gakuen University) - Title: Subaru HSC medium band filter survey and photometric redshift of galaxies
2025-02-25 16:00 - 17:00
Research Progress Meeting
Date: February 25, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Atsushi J. Nishizawa (Gifu Shotoku Gakuen University)
Title: Subaru HSC medium band filter survey and photometric redshift of galaxies
Abstract: Photometric redshift (photo-z) is a well-known technique for measuring the redshift of galaxies using imaging observations. The most challenging aspect of photo-z estimation is that the available information is quite limited, as most imaging surveys utilize broad-band filters, resulting in relatively low wavelength resolution. Traditionally, photo-z is measured by fitting model galaxy spectral energy distributions (SEDs) to the observed fluxes and determining the optimal redshift for each galaxy. An alternative approach is to estimate redshifts using machine learning methods, which can learn complex relationships between observables and redshift.
However, significant improvement in photo-z accuracy is unlikely without incorporating additional information. One possible avenue is to extend the wavelength coverage, while another is to improve the wavelength resolution. We are currently developing medium-band filters to be installed on the Hyper-Suprime Cam at the prime focus of the Subaru Telescope. These medium-band filters will offer moderate spectral resolution and high spatial resolution, providing a substantial amount of additional information. We are preparing to conduct a medium-band filter survey in the coming semesters. In this talk, we will introduce several science cases in collaboration with Euclid, the Roman Space Telescope, DESI-II, and the Subaru Prime Focus Spectrograph (PFS).
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Speaker: Ryan Bouabid (Duke) - Title: COHERENT: Using Small Recoils to Look for Big Discoveries
2025-02-27 16:00 - 17:00
Research Progress Meeting
Date: February 27, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Ryan Bouabid (Duke)
Title: COHERENT: Using Small Recoils to Look for Big Discoveries
Abstract: The COHERENT collaboration is pioneering the study of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS), a process only recently observed. Using the Spallation Neutron Source at Oak Ridge National Laboratory, COHERENT has deployed a suite of detectors using diverse technologies and targets. This talk will provide an overview of the collaboration’s experimental efforts and status. Beyond the initial measurements of CEvNS, COHERENT’s results have opened new avenues of discovery potential.
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Meeting ID: 988 5432 2464

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Speaker: Isobel Ojalvo (Princeton) - Title: Real-time Anomaly Detection at the CMS Experiment
2025-03-13 16:00 - 17:00
Research Progress Meeting
Date: March 13, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Isobel Ojalvo (Princeton)
Title: Real-time Anomaly Detection at the CMS Experiment
Abstract: During Run-3 at the LHC, the search for new physics has significantly expanded. Development of advanced algorithms for the Level-1 trigger, encompassing techniques such as Long-Lived Particles, Data Scouting, and Muon showers to ensure broad data selection at the CMS experiment. Here, we introduce CICADA (Calorimeter Image Convolutional Anomaly Detection Algorithm), a state-of-the-art, fully autonomous AI algorithm engineered to process LHC event data in real-time and trigger on anomalous topologies. Operating directly on the rawest recorded data – the calorimeter energy deposits – CICADA demonstrates sensitivity to Standard Model processes. It unveils potential for Beyond the Standard Model Physics, including the exploration of previously untapped phase space at the LHC. We will also delve into future prospects for triggering at the CMS experiment during the HL-LHC era.
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Speaker: Andrei Cuceu (LBNL) - Title: DESI DR2 results: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints
2025-03-19 15:00 - 16:00
Research Progress Meeting
Date: March 19, 2025
Time: 3:00- 4:00 pm
Location: B50 Auditorium [In-Person and HYBRID]
Speaker: Andrei Cuceu (LBNL)
Title: DESI DR2 results: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints
Abstract: The Dark Energy Spectroscopic Instrument (DESI) is conducting a 5-year redshift survey of 40 million extra-galactic sources over 14,000 square degrees of the northern sky. One of its primary goals is to measure the cosmic expansion history across a wide range of redshifts using baryon acoustic oscillations (BAO). The first DESI results, released in 2024, were based on the first year of data and showed intriguing hints that dark energy may not be described by a cosmological constant. On March 19th we will announce a new set of BAO measurements which are based on the first three years of DESI data. We will also present the cosmological implications of these measurements alone and in combination with cosmic microwave background, supernovae, and weak lensing experiments. These include constraints on the expansion rate of the Universe, the nature of dark energy, and the sum of the neutrino masses.
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Meeting ID: 919 5791 3705
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Speaker: Dean Robinson (LBNL) - Title: New Theory Tools for the Next Generation of Precision Flavor
2025-03-20 16:00 - 17:00
Research Progress Meeting
Date: March 20, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Dean Robinson (LBNL)
Title: New Theory Tools for the Next Generation of Precision Flavor
Abstract: The interpretation of upcoming precision flavor data will require a suite of higher-order calculations and theory descriptions for heavy flavor hadronic processes. We’ll discuss new developments and insights in heavy quark effective theory, that show promise to enable the next generation of precision semileptonic measurements and the interpretation and/or resolution of longstanding anomalies. We’ll also discuss status and plans for the Hammer software library, that is now used across the semileptonic experimental program.
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Speaker: Daniela Köck (University of Oregon) - Title: Exploring Electroweak Paths Beyond the Standard Model with ATLAS
2025-03-27 16:00 - 17:00
Research Progress Meeting
Date: March 27, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Daniela Köck (University of Oregon)
Title: Exploring Electroweak Paths Beyond the Standard Model with ATLAS
Abstract: Phenomenological observations such as dark matter in the universe have long hinted at physics beyond the Standard Model of Particle Physics. The Large-Hadron-Collider (LHC) at CERN has unprecedented capabilities to narrow down on models beyond the Standard Model. Hunting for supersymmetric particles has been a part of the search program since the start of the LHC. Even with these extensive explorations, some well-motivated unexplored parameter spaces only now start to become accessible.
This presentation will give an overview of the current status of searches for supersymmetry produced in electroweak interactions with the ATLAS detector. It will give an overview of the search programme carried out throughout Run-2 of the LHC, discuss a few recent highlights and motivate the necessity of future searches for electroweak supersymmetry.
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Speaker: Harry Teplitz (Caltech/IPAC) - Title: Euclid: an ESA Mission with NASA Involvement to Study the Dark Universe
2025-04-08 16:00 - 17:00
Research Progress Meeting
Date: April 8, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Harry Teplitz (Caltech/IPAC)
Title: Euclid: an ESA Mission with NASA Involvement to Study the Dark Universe
Abstract: Euclid is a European Space Agency mission with NASA involvement to study the geometry and nature of the dark universe. It is optimized for two of the primary probes of dark energy: weak gravitational lensing and galaxy clustering. Euclid launched on 1 July 2023 on a SpaceX Falcon 9 from Cape Canaveral. During its 6 year primary mission, Euclid will survey over 13,000 sq.deg. of extragalactic sky and obtain optical images (530-920nm band), near-infrared images (Y,J,H) and slitless near-infrared grism spectra (1206nm-1892nm, R~480). All Euclid data will be made public to the world community after a proprietary period. Euclid’s first large data set of over 60 square degrees was released on March 19, 2025 (Quick Release 1 or Q1), and the first year of data (about 2000 square degrees) will be released in 2026. I will give an overview of Euclid’s science goals, observing status, and the Q1 data and results.

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Meeting ID: 956 7989 2182
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Speaker: Victoria Xu (UCB) - Title: Broadband quantum enhancement of the LIGO detectors with frequency-dependent squeezing
2025-04-17 16:00 - 17:00
Research Progress Meeting
Date: April 17, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Victoria Xu (UCB)
Title: Broadband quantum enhancement of the LIGO detectors with frequency-dependent squeezing
Abstract: Quantum noise imposes a fundamental limitation on the sensitivity of laser-interferometric gravitational-wave detectors like LIGO, manifesting as shot noise and quantum radiation pressure noise. We present the realization of frequency-dependent squeezing for the fourth astrophysical observing run of the LIGO detectors, resulting in the reduction of both shot noise and quantum radiation pressure noise, alongside broadband detector sensitivity enhancement from tens of hertz to several kilohertz. We further show that frequency-dependent squeezing enables astrophysical operation with quantum noise squeezed below the Standard Quantum Limit by almost 3 dB around 50 Hz, where the LIGO detectors are most astrophysically sensitive. Frequency-dependent squeezing was enabled by the addition of a 300-meter-long in-vacuum filter cavity at each detector, as part of the A+ upgrade to Advanced LIGO. For the LIGO Hanford detector, squeezing reduced the detector noise power by ~5 dB near 1 kHz; for the Livingston detector, detector noise power was reduced by ~6 dB. Combined with technical noise improvements, the quantum upgrade to frequency-dependent squeezing has expanded the detectors’ astrophysical range by almost 20% with respect to no squeezing, and thus improved astrophysical trigger rates by up to 70% during the ongoing fourth observing run of the LIGO detectors.
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Meeting ID: 988 5432 2464

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Speaker: Michael Williams (LBNL) - Title: First Above-Ground Dark Matter Search Results from the TESSERACT Collaboration
2025-04-24 16:00
Research Progress Meeting
Date: April 24, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Michael Williams (LBNL)
Title: First Above-Ground Dark Matter Search Results from the TESSERACT Collaboration
Abstract: The TESSERACT collaboration will search for dark matter particles with masses below that of the proton using two novel, ultra-sensitive detector technologies: SPICE and HeRALD. These detectors are designed to deliver world-leading sensitivity to a broad range of low-mass dark matter candidates. In this talk, I will share recent progress in the development of Transition Edge Sensors (TESs) with sub-eV energy resolution, a critical advancement enabling the next generation of low-mass dark matter searches. I will focus on our improved understanding of the “low energy excess” background commonly observed in cryogenic detectors, along with new techniques developed to discriminate this background from potential signals. This will culminate in discussion of TESSERACT’s first above-ground dark matter search, which achieved world-leading sensitivity to dark matter masses below 87 MeV/c², powered by the most sensitive athermal phonon sensors ever deployed.
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Meeting ID: 988 5432 2464

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Speaker: Kevin O'Brien (MIT) - Title: Broadband quantum-limited amplification and near-ultrastrong light-matter coupling with superconducting circuits
2025-05-01 16:00 - 17:00
Research Progress Meeting
Date: May 1, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Kevin O’Brien (MIT)
Title: Broadband quantum-limited amplification and near-ultrastrong light-matter coupling with superconducting circuits
Abstract: Superconducting qubits are one of the leading quantum computing platforms in part due to the nonlinearity of the Josephson junction. High quantum efficiency broadband amplification is a key requirement for high fidelity qubit readout and thus implementing quantum error correction. We illustrate the modeling and design of high quantum efficiency broadband parametric amplifiers using our open source package JosephsonCircuits.jl [1]. These amplifiers are engineered to match the Floquet modes in the amplifier to the eigenmodes of the environment, eliminating a previously ubiquitous noise mechanism in broadband amplifiers [2]. We present the fabrication of such amplifiers using a high-Q qubit fabrication process with state of the art junction critical current uniformity. We detail the characterization of these amplifiers including the highest reported quantum efficiency for a traveling wave parametric amplifier [3] and future directions of on-chip integration and isolation. Finally, we show how qubits with quartic [4] rather than the familiar weakly anharmonic potential enable the first demonstration of near-ultrastrong nonlinear coupling [5] with applications in fast qubit readout [6] and gates.
[1] K. Peng, R. Poore, P. Krantz, D. E. Root, and K. P. O’Brien “X-parameter based design and simulation of Josephson traveling-wave parametric amplifiers for quantum computing applications” IEEE QCE22 (2022)
[2] K. Peng, M. Naghiloo, J. Wang, G. D. Cunningham, Y. Ye, and K. P. O’Brien “Floquet-Mode Traveling-Wave Parametric Amplifiers” PRX Quantum 3, 020306 (2022)
[3] J. Wang*, K. Peng*, G. D. Cunningham, A. Lombo, A. Yen, D. Zaidenberg, W. D. Oliver, K. P. O’Brien “High-Efficiency, Low-Loss Floquet-Mode Traveling-Wave Parametric Amplifier” arxiv 2503.11812 (2025)
[4] Y. Ye, K. Peng, M. Naghiloo, G. Cunningham, K. P. O’Brien “Engineering purely nonlinear coupling between superconducting qubits using a quarton” Physical Review Letters 127 (5), 050502 (2022)
[5] Y. Ye, J. B. Kline, A. Yen, G. Cunningham, M. Tan, A. Zang, M. Gingras, B. M. N., H. Stickler, K. Serniak, M. E. Schwartz, K. P. O’Brien “Near-ultrastrong nonlinear light-matter coupling in superconducting circuits” arXiv:2404.19199 (2024)
[6] Y. Ye, J. B. Kline, S. Chen, A. Yen, K. P. O’Brien “Ultrafast superconducting qubit readout with the quarton coupler” Science Advances 10 (41), eado9094 (2024)
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Meeting ID: 988 5432 2464

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Speaker: Josh Dillon (UC Berkeley) - Title: Recent Progress in 21 cm Cosmology with the Hydrogen Epoch of Reionization Array
2025-05-08 16:00 - 17:00
Research Progress Meeting
Date: May 8, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Josh Dillon (UC Berkeley)
Title: Recent Progress in 21 cm Cosmology with the Hydrogen Epoch of Reionization Array
Abstract: 21 cm cosmology promises a revolutionary new probe of the astrophysics and cosmology of the Cosmic Dawn and the epoch of reionization (EoR). I will discuss our progress with the Hydrogen Epoch of Reionization Array (HERA), an interferometer in South Africa with 350 14-m dishes, purpose-built for 21 cm cosmology. With early HERA data and only a small fraction of its final size and bandwidth, we have set world-leading limits on the 21 cm power spectrum. These results already have important astrophysical implications: they largely rule out “cold reionization” scenarios, provide a lower bound on the X-ray heating of the intergalactic medium, and constrain models of its origin. We are now preparing our first limits from HERA’s new broadband system (5 < z < 25), which should lay the groundwork for future results that realize the instrument’s full potential. In this talk, I will present these limits, their interpretation, and their statistical validation. Finally, I will look forward to the exciting science we can expect in the next few years from HERA, as well as the lessons it holds for future arrays for 21 cm cosmology.
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Meeting ID: 988 5432 2464

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Speaker: Ryan Roberts (LBNL) - Title: Measuring the Top Yukawa Coupling with Graph Neural Networks
2025-06-17 16:00 - 17:00
Research Progress Meeting
Date: June 17, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Ryan Roberts (LBNL)
Title: Measuring the Top Yukawa Coupling with Graph Neural Networks
Abstract: The top Yukawa coupling is a key prediction of the Standard Model and has been relatively inaccessible before Run-2 at the LHC. It has ties to many of the big questions surrounding the SM, including the fermion mass hierarchy, vacuum stability, the hierarchy problem, and the nature of the Higgs sector. Sensitive final states, including top-associated Higgs production and four-top production, have complex signatures which are natural targets for advanced machine learning techniques such as graph neural networks (GNNs). This talk presents the observation of four-top production, achieved with a graph neural network, and subsequent constraints on the Higgs boson’s coupling to top quarks and the total width of the Higgs boson. The interplay between physics objectives and developments in machine learning techniques drives the development of new strategies to maximize the physics output of the LHC program, including the sensitivity of future top Yukawa measurements.

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Speaker: Bob Hirosky (Virginia) - Title: High resolution calorimetry from the LHC to a future Higgs Factory
2025-06-26 16:00 - 17:00
Research Progress Meeting
Date: June 26, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Bob Hirosky (Virginia)
Title: High resolution calorimetry from the LHC to a future Higgs Factory
Abstract: High Energy Physics experiments employ calorimeters using various technologies for the measurement of high energy particles. This talk will review the detector physics and some challenges of precision measurements with the CMS homogeneous crystal calorimeters and discuss preparations to achieve the physics goals of the High Luminonisty LHC.
Looking forward to a future Higgs Factory I will summarize some of the international planning efforts for new detector concepts, including the CalVision/MaxiCC R&D programs which aim to produce a new, hybrid dual-readout calorimeter to achieve state-of-the-art calorimetric measurements of all final state particles.
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Meeting ID: 988 5432 2464

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Speaker: Marco Bonici (Waterloo) - Title: Taming projection effects in galaxy clustering analysis
2025-07-01 16:00 - 17:00
Research Progress Meeting
Date: July 1, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Marco Bonici (Waterloo)
Title: Taming projection effects in galaxy clustering analysis
Abstract: The analysis of galaxy clustering measurements from surveys like Euclid or DESI is likely to be affected by the so called projection effects, which causes the 1D marginals of the analysis to not contain the bestfit; this is a serious issue which can potentially harm the cosmological interpretation of these analyses. I will outline three complementary strategies to mitigate this bias: (i) simulation-calibrated priors, (ii) a frequentist framework based on profile likelihoods, and (iii) a Bayesian re-parameterisation that isolates degenerate directions. Applied to full shape data, each method reduces the impact of projection effects. I will present the reduction of the projection effects for each technique when applied to DESI data.
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Speaker: Nicole Hartman (Technical University of Munich) - Title: b-tagging unlocks the Higgs Potential — deep learning for jet flavour tagging on ATLAS
2025-07-03 12:00 - 13:00
Research Progress Meeting
Date: July 3, 2025
Time: noon – 1:00 pm [note special time]
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Nicole Hartman (Technical University of Munich)
Title: b-tagging unlocks the Higgs Potential — deep learning for jet flavour tagging on ATLAS
Abstract:
Electroweak symmetry breaking involves a Higgs potential that generates mass for the weak bosons. In the Standard Model, this potential has a quartic form—but this is merely an ansatz that has yet to be experimentally verified. A first experimental probe of the Higgs potential could come from measuring the simultaneous production of two Higgs bosons (“di-Higgs”). This is an exceptionally rare process, expected to require another decade of data collection to discover using current analysis methods. The most probable decay mode of a Higgs boson is into a pair of b-quarks, which in turn produce b-jets in the detector. The channels driving di-Higgs sensitivity therefore all include b-jets in the final state.
Machine learning is transforming many areas of life, and particle physics is no exception. Because of the complexity of jets at the LHC, b-jet classification (or flavour tagging) has become a leading application of deep learning in the field. This seminar presents the state-of-the-art in flavour tagging: a transformer model, the same backbone architecture used in ChatGPT. These modern transformers deliver an impressive factor-of-four improvement in performance compared to earlier b-taggers based on recurrent neural networks. In addition, transformers are more data-efficient, allowing us to benefit from a tenfold increase in training statistics. Importantly, these gains in simulation also translate to actual LHC data.
Transformers are general-purpose architectures that can be integrated at multiple stages of the analysis pipeline. As training datasets continue to grow, we can begin to view jet tagging as a foundation model for LHC physics—one that can be customized or “fine-tuned” for specific physics goals. We conclude by highlighting how an end-to-end optimizable analysis can fine-tune a jet-tagger for an HH physics search, helping to further advance our di-Higgs program and quest to understand the Higgs potential.

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Meeting ID: 988 8101 1162
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Speaker: Michael Reh (Boulder) - Title: Improving the Super-Kamiokande Analysis in the T2K Experiment
2025-07-10 16:00 - 17:00
Research Progress Meeting
Date: July 10, 2025
Time: 4:00- 5:00 pm
Location: This is a virtual event. Please see zoom link below.
Speaker: Michael Reh (Boulder)
Title: Improving the Super-Kamiokande Analysis in the T2K Experiment
Abstract: The Tokai-to-Kamioka (T2K) Experiment is a long baseline neutrino oscillation experiment located in Japan. T2K searches for muon neutrino disappearance and electron neutrino appearance oscillations at its far detector, Super-Kamiokande (SK). When performing the T2K neutrino oscillation analysis, the SK detector performance and reconstruction must be well understood in order to be certain of the number of muon and electron neutrino events observed. The T2K event reconstruction algorithm fiTQun does well to classify simulated electron and muon events in the detector, however differences in reconstruction performance between simulated and real data events can bias the T2K analysis results. In this seminar, the methods for estimating the T2K-SK detector reconstruction uncertainty will be discussed, including significant upgrades that include events with multiple visible particle final states in the T2K-SK analysis for the first time.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]

Speaker: Regina Demina (U of Rochester) - Title: How Quantum Are Elementary Particles? Exploring Entanglement and the Quest for Toponium
2025-07-15 16:00 - 17:00
Research Progress Meeting
Date: July 15, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Regina Demina (University of Rochester)
Title: How Quantum Are Elementary Particles? Exploring Entanglement and the Quest for Toponium

Abstract: While quantum mechanics underpins particle physics, truly quantum effects are surprisingly difficult to establish in high-energy interactions. A rare exception comes from recent observations of quantum entanglement in top–antitop quark pairs by the ATLAS and CMS experiments. In certain regions of phase space, these particles appear to lie outside the causality cone, making the result even more intriguing. In this talk, I will review the details of these groundbreaking measurements, their implications, and potential criticisms. Some deviation in the observed level of correlation between top and antitop quarks resulted in an exciting discovery of toponium, a bound state of top and antitop quarks observed by CMS. Recently confirmed by Atlas, toponium is the heaviest known composite particle, with a mass of 343 GeV—surpassing even the heaviest nucleus, Oganesson, at 279 GeV.
Join Zoom Meeting
https://lbnl.zoom.us/j/95679892182?pwd=[REDACTED]
Meeting ID: 956 7989 2182
Passcode: [REDACTED]

Speaker: Alex Wang (UCSC) - Title: Searching for di-Higgs production with the bbγγ final state: early Run 3 and beyond
2025-07-24 16:00 - 17:00
Research Progress Meeting
Date: July 24, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Alex Wang (UCSC)
Title: Searching for di-Higgs production with the bbγγ final state: early Run 3 and beyond
Abstract: Since the discovery of the Higgs boson by the ATLAS and CMS experiments in 2012, many of its properties have been constrained by precision measurements using LHC Run 2 data. One notable exception is the Higgs self coupling lambda, which modifies the shape of the Higgs potential and, in the Standard Model, is completely determined by the Higgs mass and vacuum expectation value. A value of lambda different from the Standard Model prediction could have profound implications for particle physics and cosmology. The simultaneous production of two Higgs bosons (di-Higgs), is the most accessible way to study this coupling at the LHC but presents experimental challenges due to its low production cross-section, about three orders of magnitude smaller than that of single Higgs.
In this talk, I will present the latest ATLAS search for di-Higgs production with the bbγγ final state, in which one Higgs decays into a pair of b-quarks and the other decays into a pair of photons. This is one of the most experimentally powerful channels due to the high H->bb branching ratio and the excellent ATLAS photon resolution. With the inclusion of the Run 2 (2015 – 2018) and early Run 3 (2022 – 2024) LHC datasets, these new results constitute both the first ATLAS result using over 300ifb of data and also the world’s best single-channel di-Higgs constraints to-date. Finally, I will discuss the latest prospects for the High Luminosity LHC, which is expected to increase the dataset by over a factor of 10 and bring us within observation of di-Higgs production.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]

Speaker: Nicola Neri (INFN) - Title: Probing Charm Baryon Dipole Moments at the LHC with ALADDIN
2025-08-14 16:00 - 17:00
Research Progress Meeting
Date: August 14, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Nicola Neri (INFN)
Title: Probing Charm Baryon Dipole Moments at the LHC with ALADDIN
Abstract: The magnetic and electric dipole moments (MDM and EDM) of charm baryons have yet to be measured. These fundamental properties are sensitive probes of non-perturbative QCD dynamics and potential signatures of physics beyond the Standard Model. The proposed ALADDIN experiment at the LHC aims to perform the first direct measurement of charm baryon dipole moments by exploiting spin precession in bent crystals, within a dedicated fixed-target setup.
In this novel scheme, protons from the LHC beam halo are steered by a bent crystal (“crystal kicker”) onto a tungsten target, producing charm baryons with energies up to the TeV scale. These baryons are then captured and channeled by a second bent crystal, where their spins undergo precession under strong electromagnetic fields — allowing the extraction of their dipole moments.
A recent proof-of-principle test, TWOCRYST, has successfully demonstrated the viability of this two-crystal configuration in the LHC environment. These results are a key step in validating the experimental concept and guiding the optimization of the ALADDIN setup.
In this talk, I will present the physics case for ALADDIN, detail the experimental technique and detector concept, and provide an update on ongoing detector R&D efforts. I will also report on recent results from the TWOCRYST test, which mark a significant milestone toward realizing this ambitious measurement program.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]

Speaker: Darcy Newmark (MIT) - Title: Scintillation and Cherenkov Light Separation in a Liquid Argon Detector
2025-08-21 16:00 - 17:00
Research Progress Meeting
Date: August 21, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Darcy Newmark (MIT)
Title: Scintillation and Cherenkov Light Separation in a Liquid Argon Detector
Abstract: This talk will present the first event-by-event observation of Cherenkov radiation from sub-MeV electrons in a high-yield scintillator (liquid argon) detector, representing a milestone in low-energy particle detector development and one of the major goals of 2021 Snowmass Process. This work utilizes the Coherent CAPTAIN-Mills (CCM) experiment, a 10-ton liquid argon light collection detector located at the Los Alamos National Lab pion decays at rest source. The detector is instrumented with 200 8-inch PMTs, 80% of which are coated in a wavelength shifter and 20% are uncoated. Using gamma-rays from a sodium-22 radioactive source, we have isolated prompt Chernekov light with >5 sigma confidence, possible through the unique combination of coated and uncoated PMTs. Cherenkov light identification allows for a highly pure selection of electromagnetic events, enabling exciting beyond Standard Model physics searches that I will review.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]

Speaker: Ben Allanach (Cambridge) - Title: Z' bosons in light of B-anomalies
2025-08-28 16:00 - 17:00
Research Progress Meeting
Date: August 28, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Ben Allanach (Cambridge)
Title: Z’ bosons in light of B-anomalies
Abstract: Many measurements of b->s transitions (when accompanied by a di-muon pair) disagree with state-of-the-art Standard Model (SM) predictions. On the other hand, many other measurements, including those measuring lepton flavour universality, are in rough agreement with the SM.
We shall review such measurements and give a broad overview of the SM predictions. Z’ bosons with family-dependent couplings can significantly improve global fits. We give an example of a successful model, re-cast LHC searches for it and provide HL-LHC sensitivity estimates.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]

Speaker: Heather Gray (LBNL) and Simone Pagan Griso (LBNL) - Title: What's next for CERN? Summary of the 2025 European Strategy for Particle Physics Open Symposium
2025-09-04 15:30 - 16:30
Research Progress Meeting
Date: September 4, 2025
Time: 3:30pm-4:30pm [Note special time]
Location: 50-4-Auditorium [Note special location]
Speaker: Heather Gray (LBNL) and Simone Pagan Griso (LBNL)
Title: What’s next for CERN? Summary of the 2025 European Strategy for Particle Physics Open Symposium
Abstract: CERN is undergoing a planning exercise to determine its long-term strategy in particle physics; this exercise has some similarity to the Snowmass/P5 process, but with some differences.
Center to this strategy is what large-scale projects CERN will be undertaking after the LHC and its upgraded High-Luminosity LHC operations stop at around 2041.
This symposium represented the only general open meeting to showcase the current ideas and the received community inputs that were due in March 2025. It represented a middle-point before the appointed group starts drafting a report that is expected to be preliminarily available around the end of the year.
In this seminar, we will summarize what has been shown and give our main take-aways from this symposium and the strategy process.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]

Speaker: Alan Poon (LBNL) - Title: Recent Results and Status of the Neutrinoless Double-Beta Decay Experiment LEGEND
2025-09-11 16:00 - 17:00
Research Progress Meeting
Date: September 11, 2025
Time: 4:00pm-5:00pm
Location: 70A-3-3377 [Note special location]
Speaker: Alan Poon (LBNL)
Title: Recent Results and Status of the Neutrinoless Double-Beta Decay Experiment LEGEND
Abstract: The Large Enriched Germanium Experiment for Neutrinoless ββ Decay (LEGEND) is a phased international program designed to answer one of the highest-priority questions in fundamental physics — whether neutrinos are their own anti-particles. Its first phase, LEGEND-200, reuses the cryostat of a previous-generation experiment, GERDA, in Hall A of the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy to house up to 200 kg of 76Ge-enriched high-purity germanium (HPGe) detectors. In this talk, I will present the latest results from LEGEND-200’s search for the lepton-number-violating neutrinoless double-beta decay. I will also provide a synopsis of the planning of the second phase of the experiment, LEGEND-1000.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]

Speaker: Daniel Baxter (Fermilab) - Title: A QUIET place: Fermilab’s Underground Facilities for Quantum Sensing
2025-09-16 16:00 - 17:00
Research Progress Meeting
This is a joint seminar with the Interdisciplinary Instrumentation Colloquium (IIC).
Date: September 16, 2025
Time: 4:00- 5:00 pm
Location: 50-4-Auditorium [Note location] [In-Person and HYBRID]
Speaker: Daniel Baxter (Fermilab)
Title: A QUIET place: Fermilab’s Underground Facilities for Quantum Sensing

Abstract: The infrastructure associated with building a large accelerator complex created some very unique spaces at Fermilab. In particular, the MINOS tunnel, excavated as part of the NuMI neutrino beam delivering neutrinos to the MINOS, MINERVA, and NOVA experiments, is an easily-accessible 100m underground experimental space. The rock overburden at this depth blocks 99.5% of all cosmic ray muons, and nearly all hadronic showers, creating a unique, low-background environment for novel detector development and calibration.
The NEXUS and QUIET laboratories, each equipped with dilution refrigerators for 10mK detector operation, are harnessing this opportunity. I will highlight the unique capabilities of these testbeds, as well as some of the interesting results that have come out of them. I will briefly touch on some of our ongoing studies and proposed experiments for the near future.
Join Zoom Meeting
https://lbnl.zoom.us/j/97314813383?pwd=[REDACTED]
Meeting ID: 973 1481 3383
Passcode: [REDACTED]

Speaker: Jim Strait (LBNL) - Title: CMB-S4: birth, life and death of a major science project
2025-09-25 16:00 - 17:00
Research Progress Meeting
Date: September 25, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Jim Strait (LBNL)
Slides: Download slides
Title: CMB-S4: birth, life and death of a major science project
Abstract: CMB-S4 was envisioned to be a comprehensive ground-based CMB experiment to make transformative discoveries and new insights in fundamental physics, cosmology, astrophysics, and astronomy. It was conceived as a way to unite the entire CMB community to enable a ground-based experiment with capabilities beyond that of any of the smaller individual experiment to realize the enormous potential of CMB measurements for understanding the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. CMB-S4 was launched with great promise and enthusiasm at the 2013 Snowmass Summer Study, grew into a large collaboration, built a capable project organization, developed an advanced technical design and scientific strategies, was endorsed by multiple high-level advisory committees, but ultimately was cancelled by the funding agencies in 2025. In this talk I will summarize the history and accomplishments of CMB-S4, and provide an analysis of why it did not succeed.
https://lbnl.zoom.us/j/98854322464?pwd=[REDACTED]
Meeting ID: 988 5432 2464

Passcode: [REDACTED]
