LBNL Physics Division Research Progress Meetings

Speaker: Lloyd Knox (UC Davis) - Title: A Polarized Look at the Hubble Constant Problem
2025-01-16 16:00 - 17:00 UTC
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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Speaker: Ryan Gibbons (UC Berkeley) - Title: Searching for Dark Matter with LZ and Future LZ Upgrades
2024-12-19 16:00 - 17:00
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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Speaker: Sparshita Dey (Oxford) - Title: Chasing Shadows: Illuminating the Path from LZ to the Next Generation Dual-Phase Xe TPC Observatory for Dark Matter
2024-12-17 16:00 - 17:00
Research Progress Meeting
Date: December 17, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Sparshita Dey (Oxford)
Title: Chasing Shadows: Illuminating the Path from LZ to the Next Generation Dual-Phase Xe TPC Observatory for Dark Matter
Abstract: The nature of dark matter remains one of the most significant unsolved challenges in modern physics. Liquid xenon time projection chambers (LXe-TPCs) have emerged as a powerful tool in the search for WIMP dark matter candidates (Weakly Interacting Massive Particles), particularly in the GeV/c2 range. The XENON-LUX-ZEPLIN-DARWIN (XLZD) collaboration embodies the collective knowledge & expertise of generations of LXe-TPC-based experiments, combining three current world-leading experimental and R&D efforts operating at sub-10-tonne Xe target masses. This talk will present the case for XLZD’s next-generation dual phase xenon observatory for dark matter and neutrino physics, with the capability to explore the WIMP parameter space down to the so-called neutrino fog, a background-limited region where neutrino and WIMP signatures look very similar. A discussion of the lessons learned from the operation & analysis chain for the LUX-ZEPLIN experiment will feature, to motivate the design approach for this detector, as well as an overview of novel detector design concepts and exciting current R&D experiments which may both improve sensitivities to low-mass dark matter models and revolutionise the current dark matter direct detection landscape.
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Speaker: Shion Kubota (Harvard) - Title: Studying neutrinos in high definition with LAr
2024-12-12 16:00 - 17:00
Research Progress Meeting
Date: December 12, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Shion Kubota (Harvard)
Title: Studying neutrinos in high definition with LAr
Abstract: This talk explores recent advancements in neutrino physics, with a focus on innovative detector technologies developed for the Deep Underground Neutrino Experiment (DUNE). It delves into the use of Liquid Argon Time Projection Chambers (LArTPCs), discussing the challenges associated with the Anode Plane Assembly’s (APA) quality control and how the Digital Wire Analyzer (DWA) has improved the efficiency of wire tension testing. Additionally, the presentation introduces the Q-Pix readout architecture, a promising approach to pixelated detection that streamlines data handling and enhances studies of supernova neutrinos. Simulation results highlight Q-Pix’s potential to improve event reconstruction, extend detection capabilities, and reduce data demands, offering exciting possibilities for future kiloton-scale neutrino experiments.
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Speaker: Tyler Horoho (U. of Virginia) - Title: Searching for sub-GeV Dark Matter with the NOvA Near Detector and Measuring the Performance of the Mu2e Cosmic Ray Veto
2024-12-10 16:00 - 17:00
Research Progress Meeting
Date: December 10, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Tyler Horoho (U. of Virginia)
Title: Searching for sub-GeV Dark Matter with the NOvA Near Detector and Measuring the Performance of the Mu2e Cosmic Ray Veto
Abstract: The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for the origin of dark matter sharpen the focus to within about an MeV to 100 TeV. Most of the stable constituents of known matter have masses in this lower range, and a thermal origin for dark matter works in a simple and predictive manner. If there is a non-gravitational interaction between dark matter and ordinary matter, as there must be in the case of a thermal origin, then there is necessarily a production mechanism in accelerator-based experiments. NOvA is a high luminosity long-baseline neutrino oscillation experiment at Fermilab that is capable of searching for signatures of dark matter re-scattering with electrons in its near detector after production in the NuMI target. In this talk, I present an analysis to search for an excess of single electron events in the NOvA near detector consistent with the presence of dark matter-electron scattering and show the expected sensitivity of NOvA to sub-GeV dark matter. I will also discuss a future search for sub-GeV dark matter with the Light Dark Matter eXperiment (LDMX), a planned electron-beam fixed-target missing-momentum search for dark matter at SLAC.
The Mu2e experiment at Fermilab will search for charged-lepton flavor violation through the neutrino-less conversion of a muon to an electron in the presence of a nucleus, a sensitive probe for new physics. Mu2e aims to have single-event sensitivity four orders of magnitude beyond current experimental limits. This sensitivity will require less than one expected background event, which will only be possible with sufficient background vetoing. The largest source of background comes from cosmic-rays, which can produce electrons indistinguishable from a conversion electron signature. To mitigate this, Mu2e will use a cosmic ray veto (CRV), which must exceed a veto efficiency of 99.99% to meet Mu2e’s sensitivity goals. I will present performance studies on the CRV detector components.
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Speaker: Cole Kampa (Northwestern U.) - Title: From Muon CLFV to Collider EFT: Advances in New Physics Searches
2024-12-05 16:00 - 17:00
Research Progress Meeting
Date: December 5, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Cole Kampa (Northwestern U.)
Title: From Muon CLFV to Collider EFT: Advances in New Physics Searches
Abstract: Mu2e, the muon-to-electron conversion experiment at Fermilab, will search for Charged Lepton Flavor Violation (CLFV) – an accidental symmetry forbidden in the Standard Model (SM) of particle physics. Observing CLFV would provide unambiguous evidence of New Physics (NP) beyond the SM. I will briefly outline the experimental design and methodology of Mu2e, emphasizing ongoing efforts to ensure robust physics results. Notably, the introduction of an unbinned maximum likelihood fit has improved the expected sensitivity to Rμe, the muon-to-electron conversion rate, by up to 20%. On the apparatus side, a key component of the experiment is the tracking detector, which reconstructs electron trajectories in a uniform magnetic field. Studies of numerical calculations of the field suggest the calculations should predict the field with 1e-3 level accuracy. However, a 1e-4 level accuracy is required to distinguish signal electrons from the dominant muon decay-in-orbit (DIO) background. To meet this challenge, a custom field mapping apparatus is being developed. The measured field data will be modeled using a novel approach that combines least-squares fitting with a scalar physics-informed neural network (PINN), achieving a modeling fidelity significantly better than the 1e-4 accuracy requirement. I will conclude the CLFV discussion with an overview of two next-generation experiments: Mu2e-II and the Advanced Muon Facility (AMF).

The energy frontier offers a complementary path to NP discovery. Although direct searches at the Large Hadron Collider (LHC) have yet to yield definitive signs of NP, many efforts now focus on model agnostic approaches such as Effective Field Theory (EFT). Recently, the Compact Muon Solenoid (CMS) collaboration observed SM triboson (VVV) production. Building on this milestone, an ongoing CMS analysis employs an EFT framework to constrain heavy NP given the observed rate of VVV. I will conclude by discussing the statistical combination of the various final states being explored in this analysis.
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Speaker: Simon Koch (Oxford) - Title: Measurements with ATLAS, Measurements of ATLAS: A search for leptoquarks in a final state with two tau leptons, and material measurements of the ITk Pixel detector
2024-12-03 16:00 - 17:00
Research Progress Meeting
Date: December 3, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Simon Koch (Oxford)
Title: Measurements with ATLAS, Measurements of ATLAS: A search for leptoquarks in a final state with two tau leptons, and material measurements of the ITk Pixel detector
Abstract: The ATLAS detector at the LHC has enjoyed great success so far, spanning both new discoveries and precision measurements, and tests of a vast array of theoretical models. This seminar will begin with an introduction to the ATLAS high-mass Drell-Yan di-tau measurement and in particular the search for leptoquarks in this decay channel, including the analysis design and expected results. The search was originally motivated by hints toward lepton-flavour-universality violating behaviour at LHCb, and the leptoquark models explored couple the lepton and quark sectors of the standard model via a new vector or scalar boson. This also introduces unique properties and challenges to the analysis, such as the impact of negative interference with the standard model cross-section.
The future should bring an even greater physics reach thanks to the larger datasets that will be made possible by the High-Luminosity LHC and the ATLAS Inner Tracker (ITk) upgrade. The tracking and vertexing performance of the ITk is critical for future analyses, and hence factors influencing detector performance must be validated so they can be correctly implemented in our Monte-Carlo simulations. One important aspect is the material content of the detector, which has a substantial impact on b-tagging and vertexing resolution due to multiple scattering and hadronic interactions, and is generally only verified using detector data post-commissioning. The second part of this seminar will explore a series of testbeam measurements utilising multiple scattering of low-energy positrons to measure 2D maps of the fractional radiation length x/X₀ of detector components to sub-mm resolution during the R&D phase. A measurement of an ITkPix quad module will be presented, and an outlook will be given on the feasibility of measuring large areas quickly and efficiently with such a technique.
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Speaker: Gillian Kopp (Princeton University) - Title: Enabling Novel Long-Lived Particle Searches through 5D Calorimetry in the CMS Experiment
2024-11-21 16:00 - 17:00
Research Progress Meeting
Date: November 21, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Gillian Kopp (Princeton University)
Title: Enabling Novel Long-Lived Particle Searches through 5D Calorimetry in the CMS Experiment
Abstract: The Compact Muon Solenoid (CMS) experiment records proton-proton collisions from the LHC to measure properties of the Standard Model and search for new physics. Recently, long-lived particles have emerged as a compelling direction in which to search for physics beyond the Standard Model. As these searches are typically limited by the event selection, implementing dedicated long-lived particle (LLP) triggers provides an excellent avenue to expand experimental coverage into this challenging parameter space. A novel hardware-level LLP trigger has been developed and implemented in the CMS experiment for Run 3 (2022-2026), exploiting the recent hadron calorimeter (HCAL) upgrade. The hardware- and firmware-based trigger algorithm identifies delayed jets, resulting from the decay of massive LLPs, and displaced jets, resulting from LLPs that decay inside the HCAL. This approach significantly increases sensitivity to LLP signatures with soft hadronic final states, including exotic decays of the Higgs boson. I review the trigger implementation, calibration, and performance, showing results from recent HCAL timing scans that produce artificially delayed jets. The data collected with the new triggers provides a first look at the capabilities to capture softer events and expand the phase space accessible in LLP searches.
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Speaker: Claire Lamman (Harvard) - Title: Untangling the Cosmic Web: Correlations between small-scale clustering and large-scale structure
2024-11-12 16:00 - 17:00
Research Progress Meeting
Date: November 12, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Claire Lamman (Harvard)
Title: Untangling the Cosmic Web: Correlations between small-scale clustering and large-scale structure
Abstract: Gravitational forces from the largest structures in the Universe leave a detectable imprint on galaxies and their local environment. I will present a new approach to tracing the tidal field using these correlations: the intrinsic alignment of small groups of galaxies, or “multipelts”. Multiplets mostly consist of 2-4 galaxies within 1 Mpc/h of each other, and we measure their orientations relative to the galaxy-traced tidal field. Using spectroscopic redshfits from the DESI Y1 survey, we detect intrinsic alignment out to projected separations of 100 Mpc/h and beyond redshift 1. We find a simillar signal regardless of galaxy luminosity or color, which could make multiplet alignment a useful tool for mapping the direction of the tidal field and any cosmological effects which impact it. Our detection demonstrates that galaxy clustering in the non-linear regime of structure formation preserves an interpretable memory of the large-scale tidal field.

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Speaker: Taylor Hoyt (LBNL) - Title: Toward a Precision Cosmology Measurement of the Hubble Constant
2024-11-07 16:00 - 17:00
Research Progress Meeting
Date: November 7, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Taylor Hoyt (LBNL)
Title: Toward a Precision Cosmology Measurement of the Hubble Constant
Abstract: The local value of the Hubble constant (H0) derived from a Cepheid calibration of nearby supernovae (SNe) continues to disagree with values derived from a Lambda(or w)CDM interpretation of large scale cosmological datasets from, e.g., Planck or DESI. The Cepheid-SN and high-z values of H0 consistently come in close to 73 and 68 km/s/Mpc, respectively, with a latest claim that the Hubble tension has surpassed 5 sigma significance. At the same time, a calibration of the SNe based on the Tip of the Red Giant Branch (TRGB) distance indicator suggests significantly less of a tension, consistently returning values near 69.5 km/s/Mpc. This persistent local Hubble Tension indicates that classical H0 experiments have not yet reached the level of accuracy required of a “precision cosmology” measurement.
To this end, I will discuss ongoing efforts aimed at evaluating, and ultimately reducing, the amount that underestimated systematic errors could contribute to SN-derived H0 measurements and subsequently bias the evidence for or against the Hubble Tension. These efforts include: new, higher signal-to-noise distance measurements from JWST, investigations into the differing treatment of nearby SNe, and the calibration of a new methodology for SN distance measurement twice as precise and accurate as the canonical approach. These paths together will ensure a more complete understanding of the Hubble Tension, its significance (e.g., H0 tails), and will prove crucial in ushering the accuracy of local H0 measurements into the regime of precision cosmology.
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Speaker: Elisabetta Manca (UCLA) - Title: High-precision measurement of the W boson mass at CMS
2024-11-05 16:00 - 17:00
Research Progress Meeting
Date: November 5, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Elisabetta Manca (UCLA)
Title: High-precision measurement of the W boson mass at CMS
Abstract: The W boson mass is measured using proton-proton collision data at corresponding to an integrated luminosity of 16.8 inverse fb recorded during 2016 by the CMS experiment. The W boson mass is obtained from a fit of the two-dimensional pT-η distribution in a sample of W→μν decays, categorized by charge, yielding one of the most precise measurements of the W mass to date.

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Speaker: Vinicius Mikuni (LBNL) - Title: OmniLearn: A Method to Simultaneously Facilitate All Jet Physics Tasks
2024-10-31 16:00 - 17:00
Research Progress Meeting
Date: October 31, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Vinicius Mikuni (LBNL)
Title: OmniLearn: A Method to Simultaneously Facilitate All Jet Physics Tasks
Abstract: Machine learning has become an essential tool in the study of jets, collimated sprays of particles emerging from strong force interactions. Due to their complex, high-dimensional nature, jets can be explored holistically by neural networks in ways that are not possible manually. However, innovations in all areas of jet physics are proceeding in parallel. We show that specially constructed machine learning models trained for a specific jet classification task can improve the accuracy, precision, or speed of all other jet physics tasks. This is demonstrated by training on a particular multiclass generation and classification task and then using the learned representation for different generation and classification tasks, for datasets with a different (full) detector simulation, for jets from a different collision system (pp versus ep), for generative models, for likelihood ratio estimation, and for anomaly detection. Our OmniLearn approach is thus a foundation model and is made publicly available for use in any area where state-of-the-art precision is required for analyses involving jets and their substructure.
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Speaker: Kaja Rotermund (LBNL) - Title: LuSEE-Night – the Dark Ages from the Far Side of the Moon
2024-10-24 16:00 - 17:00
Research Progress Meeting
Date: October 24, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Kaja Rotermund, LBNL
Title: LuSEE-Night – the Dark Ages from the Far Side of the Moon
Abstract: The “Dark Ages” refers to the cosmic era between the last scattering of the cosmic microwave background and “Cosmic Dawn,” the time when the first stars and galaxies formed. Only cold, non-luminous hydrogen gas existed during the Dark Ages, which emits at 21 cm (f = 1420 MHz). Through the expansion of the universe, this signal has been redshifted to low radio frequencies that are inaccessible from earth due to distortions of our ionosphere and significant terrestrial radio-frequency interference. This era is therefore largely unexplored and remains one of the least constrained frontiers of modern cosmology. LuSEE-Night is a project that aims to make sensitive measurements across two decades in frequency space from the radio-quiet far side of the moon. In doing so, LuSEE-Night will determine the feasibility of conducting radio-frequency astronomy from the lunar surface and acts as a pathfinder for larger missions in the future.
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Speaker: Julien Carron (UNIGE) - Title: Delensing the Cosmic Microwave Background
2024-10-22 16:00 - 17:00
Research Progress Meeting
Date: October 22, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Julien Carron (UNIGE)
Title: Delensing the Cosmic Microwave Background
Abstract: Gravitational lensing of the Cosmic Microwave Background is a very valuable cosmological signal, detected at very high significance by several experiments. At the same time, it has also become an hindrance to some important science goals of CMB experiments, most notably for best constraints on a primordial background of gravitational waves. After reviewing current lensing estimation techniques and recent results, I’ll discuss how removal of the lensing signal (`delensing’) typically helps measuring small parameters that affects the CMB polarization. Very sensitive experiments must rely on novel more powerful algorithms to optimally extract or remove the lensing signal: I will present the approach developed in our group in Geneva, together with its forecast performance for upcoming experiments, notably CMB-S4.
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Speaker: Ibles Olcina Samblas (LBNL) - Title: New constraints on WIMP dark matter from the LUX-ZEPLIN (LZ) experiment
2024-10-10 16:00 - 17:00
Research Progress Meeting
Date: October 10, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Ibles Olcina Samblas (LBNL)
Title: New constraints on WIMP dark matter from the LUX-ZEPLIN (LZ) experiment
Abstract: Dark matter detection experiments based on liquid xenon time projection chambers (TPC) have been steadily increasing in sensitivity to the weakly interacting massive particle (WIMP) over the past two decades. The LUX-ZEPLIN (LZ) experiment, employing a two-phase xenon TPC containing 7 tonnes of liquid xenon, leads the way. Recently, the collaboration released new results from a combined analysis using data from the 2022 and 2024 science campaigns, amounting to an exposure of 4.2 tonne-years. No evidence for an excess over expected backgrounds was found across all the test WIMP masses. The resulting limit on the spin-independent WIMP-nucleon cross section is world-leading for masses above 9 GeV/c2, surpassing previous best limits by about a factor of four. In this talk, I will describe the new LZ results—including a new technique to actively tag background electronic recoils from Pb-214 beta decays, the observation of charge-suppressed two-neutrino double electron capture events from Xe-124 decays, and the bias mitigation technique called “salting”—and briefly discuss what is on the horizon for the liquid xenon TPC community.
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Speaker: Simone Pagan Griso (LBNL) - Title: How a 10 TeV muon collider could be in the particle-physics future
2024-10-03 16:00 - 17:00
Research Progress Meeting
Date: October 3, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Simone Pagan Griso (LBNL)
Title: How a 10 TeV muon collider could be in the particle-physics future

Abstract: A Muon Collider offers the potential for a scalable path towards the next generation of high-energy frontier particle colliders. A 10 TeV center-of-mass collider would allow us to study the Standard Model of particle physics in regimes qualitatively different from what we have been able to explore so far.
At the same time, the short life-time of the muon poses non-trivial technical challenges on both the accelerator and detector design. The last P5 report recognized the high-gain possible from such a machine and refers to that as “the muon shot”.
While studies towards a muon collider have been done for decades, at various degrees of emphasis, the feasibility studies towards a 10 TeV machine have ramped up and caught more and more attention in the last few years, fueled also by the current technology possibilities and the state of the field.
The compact design also offers the possibility of hosting such a collider on the Fermilab site, which has contributed to increase more and more domestic interest as well.
A recent workshop held at Fermilab also started the discussion of forming a US-based Muon Collider organization,in cooperation with the international Muon Collider Collaboration.
In this seminar I will take the occasion of this recent workshop to give to the local crowd a quick overview of the physics case and the state of the design for the accelerator complex and detectors for such a collider, focusing on the technical opportunities and challenges ahead to make this dream-project a reality.
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Speaker: Elliot Reynolds (LBNL) - Title: Probing the associated production of the Higgs boson and charm quarks at ATLAS
2024-08-29 16:00 - 17:00
Research Progress Meeting
Date: August 29, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Elliot Reynolds (LBNL)
Title: Probing the associated production of the Higgs boson and charm quarks at ATLAS

Abstract: One of the most extraordinary discoveries about the universe is that the more of it we explain, the simpler the explanations become. The Standard Model (SM) of particle physics is the culmination of this journey, and explains most of our day-to-day world with just a handful of particles. We know, however, that the SM is incomplete, and because aspects of it still seem arbitrary, we suspect a deeper theory may lie beneath. One of the clearest examples of this is the masses of the fermions, which span many orders of magnitude, seem to have largely arbitrary values, and fall into a clear hierarchy, yet none of these facts are explained in the SM. To understand these things, we should explore how the masses of the fermions arise, which is thought to be due to their interactions with the Higgs boson. Measuring these interactions is therefore a major priority at the Large Hadron Collider, where they have already been measured for the third-generation fermions, and almost for the muon. These measurements remain elusive for the first- and second-generation quarks, though the charm quark is likely our best opportunity to remedy this. Measuring the interactions between the Higgs boson and the charm quark is proving highly challenging, however, and new methods will be needed. This talk presents the first inclusive search for the associated production of the Higgs boson and charm quarks, which uses the ATLAS detector. The search represents an unconventional avenue to probe their interaction strength, and introduces a new Higgs boson production measurement. This work also represents the first usage of Gaussian process regression for direct background estimation in a particle physics data analysis.
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Speaker: Max Swiatlowski (TRIUMF) - Title: The LHC’s Next Frontier: Searching for Pairs of Higgs Bosons to Understand the Standard Model and Beyond
2024-07-11 16:00 - 17:00
Research Progress Meeting
Date: July 11, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Max Swiatlowski (TRIUMF)
Title: The LHC’s Next Frontier: Searching for Pairs of Higgs Bosons to Understand the Standard Model and Beyond

Abstract: The discovery of the Higgs boson at the Large Hadron Collider completed the Standard Model, but many fundamental open questions in particle physics remain. One question is particularly simple: how could the Big Bang produce the matter-dominated universe we observe without anti-matter, which should have been produced in equal parts? As the LHC produces collisions faster than ever before, the huge datasets the ATLAS experiment is collecting can provide answers to this question, and others, by enabling the measurement of the extremely rare production of pairs of Higgs bosons. Though difficult to observe, these signatures can directly measure the shape of the Higgs potential: deviations from the Standard Model’s expectations could allow us to understand not just the history of the early universe that created the matter/anti-matter asymmetry, but questions like the future stability of the universe. This talk will focus on the challenges to detecting Higgs boson pairs, and how to interpret them to understand the true shape of the Higgs potential and consequences for physics beyond the Standard Model. The latest results from the ATLAS experiment will be presented, and prospects for future measurements at the High-Luminosity LHC and next-generation colliders will be discussed.
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Speaker: David Miller (University of Chicago) - Title: Black Boxes or Interpretable Models? Applications of Machine Learning, Symmetries, and Domain Knowledge to High-Dimensional Problems in Particle Physics.
2024-06-18 16:00 - 17:00
Research Progress Meeting
Date: June 18, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: David Miller (University of Chicago)
Title: Black Boxes or Interpretable Models? Applications of Machine Learning, Symmetries, and Domain Knowledge to High-Dimensional Problems in Particle Physics.
Abstract: The world of artificial intelligence (AI) and machine learning (ML) has undergone what some scientists refer to as the “3rd Age of AI” due to the confluence of developments in Algorithms, Computing Resources, and Big Data. Particle Physics has benefitted from, and in many ways strengthened and advanced, progress in AI/ML for decades due to its proliferation of enormous data sets, complex instrumentation, and enormous computing infrastructure. However, there exist both known and unknown deficiencies in our ability to explain “why” some AI/ML models yield a certain result. In this talk, I will discuss some of the context and applications of AI/ML in experimental particle physics. I will then focus on a few projects ongoing in my group that we believe target important problems relevant to the use of machine learning, symmetries, and domain knowledge in particle physics.

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Speaker: Brenda Frye (University of Arizona) - Title: Measuring the Hubble-Lemaitre Constant with James Webb Space Telescope Observations of the Lensed Supernova H0pe
2024-06-13 16:00 - 17:00
Research Progress Meeting
Date: June 13, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Brenda Frye (University of Arizona)
Title: Measuring the Hubble-Lemaitre Constant with James Webb Space Telescope Observations of the Lensed Supernova H0pe
Abstract: A review of cluster lensing in the first two years of James Webb Space Telescope (JWST) observations is presented, focussing on the JWST Guaranteed Time Observations (GTO) program the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS). These observations range from the spectacle of JWST “first light” images of the distant universe to dense galaxy cluster fields that uncovered unprecedented numbers of giant arcs and image multiplicities. A point-source was discovered in the PEARLS image of the galaxy cluster field PLCK G165.7+67.0 (G165) that is bright and appears in three different locations as a result of strong lensing. Additional JWST observations confirmed this source to be a normal Type Ia supernova (SN) at a redshift of 1.783 that we call “SN H0pe,” making it one of the highest redshift standard candles. In a blinded approach, seven independent lens models were constructed, and time delays between the images were measured in two ways, off of: (1) the light curve, and (2) model fits to the spectra of each of the three SN images. During the unblinding event, a value for H0 was inferred by rescaling the lens-model predicted time delays to match the measured time delays. This is only the second measurement of H0 by the method of a multiply-imaged supernova, and the first by a standard candle. G165 has one of the highest rates of star formation summed up over the background lensed sources, making continued monitoring potentially rewarding for the discovery of additional SNe.
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Speaker: Rachel Mannino (LLNL) - Title: Dark Matter Searches with the Axion Dark Matter eXperiment (ADMX)
2024-06-06 16:00 - 17:00
Research Progress Meeting
Date: June 6, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Rachel Mannino (LLNL)
Title: Dark Matter Searches with the Axion Dark Matter eXperiment (ADMX)
Abstract: For decades, we have been collecting indirect astrophysical evidence that ordinary matter only
comprises about 5% of the mass-energy content in the universe with the remaining split between dark
matter and dark energy. Potential dark matter candidates span a wide parameter space, and many
parallel efforts are in progress to detect and identify the nature of dark matter. The Axion Dark Matter
eXperiment (ADMX) searches for the axion, a leading low-mass dark matter candidate and a potential
solution to the strong CP problem, by searching for an axion’s conversion to two microwave photons in a
strong magnetic field. I will present an overview of ADMX’s past and present axion searches using a
single microwave cavity and the planned next generation ADMX-2A and ADMX-EFR (Extended
Frequency Range) detectors.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore
National Laboratory under Contract DE-AC52-07NA27344.
LLNL-ABS-864832
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Speaker: Emma Tolley (EPFL) - Title: Radio Cosmology: Imaging the Cosmic Dawn
2024-05-30 16:00 - 17:00
Research Progress Meeting
Date: May 30, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Emma Tolley (EPFL)
Title: Radio Cosmology: Imaging the Cosmic Dawn
Abstract: Radio astronomers are engaged in ambitious new projects to detect faster, fainter, and more distant astrophysical phenomena. The flagship project is the Square Kilometer Array Observatory (SKAO). The SKAO will use thousands of individual radio receivers linked through interferometry to create the world’s largest radio telescope with unprecedented sensitivity, field of view, and survey speed, allowing us to map the neutral hydrogen throughout our Universe from nearby galaxies to the Cosmic Dawn epoch when stars and galaxies first formed. However, as a groundbreaking observational facility, SKA introduces new astrophysical, computational, and data analysis challenges. I present an overview of computational challenges and solutions for the SKAO, new techniques for image synthesis, and applications of AI in 21cm cosmology experiments.
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Speaker: Deborah Harris (York/FNAL) - Title: Precision Neutrino Oscillation Measurements: Are we there yet?
2024-05-28 16:00 - 17:00
Research Progress Meeting
Date: May 28, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Deborah Harris (York/FNAL)
Title: Precision Neutrino Oscillation Measurements: Are we there yet?
Abstract: Neutrino Oscillations, one of the precious few signatures of beyond the standard model physics, offer an exciting opportunity to study the universe. Neutrino oscillation measurements can give us new insight into what generate particle masses and what might generate the abundance of matter over antineutrino that we currently enjoy. Making precision oscillation measurements is challenging though, in part due to their miniscule probability to interact with matter. The Deep Underground Neutrino Experiment (DUNE), currently under construction, aims to make precision measurements of neutrino oscillations across a broad range of neutrino energies, with a goal of not only getting precise oscillation parameters in the new standard “3-neutrino-flavour paradigm” but also to test the framework itself. Making precision oscillation measurements also requires a thorough understanding of the way neutrinos interact in nuclei in order to measure the oscillation probability as a function of neutrino energy. This talk will review recent progress on DUNE as well as a few recent neutrino interaction measurements from MINERvA that are helping to lay the foundations of future oscillation measurements.

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Speaker: Maria Vincenzi (Duke University) - Title: Cosmological results from the Dark Energy Survey Supernova program
2024-05-09 16:00 - 17:00
Research Progress Meeting
Date: May 9, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Maria Vincenzi (Duke University)
Title:Cosmological results from the Dark Energy Survey Supernova program
Abstract: The Dark Energy Survey Supernova sample is the largest and deepest Type Ia Supernova (SN Ia) sample from a single telescope to date. It includes 1600 photometrically identified SNe Ia with high-quality multi-band light curves and spectroscopic redshifts. With a redshift range spanning between 0.1 to 1.2 and a well-defined selection function, this SN sample constitutes an ideal dataset for cosmology. In my talk, I will present the cosmological results from this unique sample and show that DES SNe, combined with publicly available low-z SN samples, provides excellent constraints on the Dark Energy equation of state from SN Ia.
Looking towards the future, I will discuss how future optical ground-based surveys like Rubin, and space-based near-infrared observatories like the Nancy Grace Roman Space Telescope, will revolutionise SN Ia cosmology and potentially answer some of the most pressing questions of modern cosmology.
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Speakers: Career Panel (Industry) - Title: How to start a career in industry: A panel discussion with physicists who work in industry
2024-04-30 16:00 - 17:00
Research Progress Meeting
Date: April 30, 2024
Time: 4:00- 5:00 pm
Location: 50-4-Auditorium [In-Person and HYBRID]
Panelists:

Marat Freytsis (Anthropic)
Riccardo Manenti (Rigetti)
Ronald Goossens (ASML)
Kathy Copic (Fieldwork Partners)
Mark Dishner (Lam Research)
Ana Ovcharova (Ionq)

Title: How to start a career in industry: A panel discussion with physicists who work in industry
Abstract: In this panel discussion postdocs and students will have the opportunity to ask questions about how to approach a career in industry. How do you make the right connections? How to craft a compelling application? What does work-life balance look like in industry? etc etc
Most of the time will be reserved for interactions with the audience, so bring along all your questions about finding positions in industry.

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Speaker: Caterina Vernieri (SLAC) - Title: Delving into the Unknown: The Higgs Boson at Future Colliders
2024-04-25 16:00 - 17:00
Research Progress Meeting
Date: April 25, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Caterina Vernieri (SLAC)
Title: Delving into the Unknown: The Higgs Boson at Future Colliders
Abstract: The Higgs boson was discovered in 2012 by the ATLAS and CMS experiments at the world’s most powerful particle collider, the Large Hadron Collider (LHC) in Geneva, Switzerland. This particle plays a unique role in fundamental physics. It gives all of the known elementary particles, including itself, their masses. While we now have a strong evidence that the Higgs field is indeed the unique source of mass for the known elementary particles, the next step is to search for new interactions that could also explain why the Higgs field has the properties required by the Standard Model of particle physics. We have no clear roadmap to this new theory but the Higgs boson plays a crucial role in this quest. The goal of a next-generation e+e- collider is to carry out precision measurements to per-cent level of the Higgs boson properties that are not accessible at the LHC. In this talk we present the challenges and possibilities for the next e+e- collider and recent progress. The exploitation of the complementarity between LHC and future colliders will be the key to understanding fundamentally the Higgs boson.
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Speaker: Julien Guy (LBNL) - Title: The Dark Energy Spectroscopic Instrument First Year Results: Cosmic Expansion History with Baryon Acoustic Oscillations
2024-04-16 16:00 - 17:00
Research Progress Meeting
Date: April 16, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Julien Guy (LBNL)
Title: The Dark Energy Spectroscopic Instrument First Year Results: Cosmic Expansion History with Baryon Acoustic Oscillations
Abstract: The Dark Energy Spectroscopic Instrument (DESI) collaboration 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 with baryon acoustic oscillations (BAO). I will present the measurement of BAO in galaxy, quasar and Lyman-alpha forest tracers from the first year of observation. With 5.7 million galaxy and quasar redshifts in the range 0.1 < z < 2.1, and 420,000 Lyman-alpha forest quasars at higher redshift, the aggregate precision on BAO is of 0.52% at z<2.1 and 1.1% at an effective redshift z=2.3, surpassing in a year two decades of observations with the SDSS. I will present some of the numerous validation tests performed with simulations and blinded data. I will then highlight the main cosmological results, with improved constraints on the dark energy equation of state, the Hubble parameter, spatial curvature, and the sum of neutrino masses.

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Speaker: Slavomira Stefkova (Karlsruhe Institute of Technology) - Title: Glimpse of a Rare B Decay with Two Invisible Neutrinos at Belle II
2024-04-11 16:00 - 17:00
Research Progress Meeting
Date: April 11, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Slavomira Stefkova (Karlsruhe Institute of Technology)
Title: Glimpse of a Rare B Decay with Two Invisible Neutrinos at Belle II
Abstract: The decay of B+→K+νν̄ is mediated by flavor-changing neutral current. In the Standard Model, the rate for this elusive process is predicted to be 6×10^-6, while enhancements are foreseen in many New Physics models. Searching for B+→K+νν̄ decays is, however, experimentally challenging as this decay is not only rare but also contains two neutrinos, leaving no signature in the detector. In this talk, I will show you details of the newest measurement of the rate of B+→K+νν̄ decays, which is based on 362 fb^-1 of SuperKEKB electron-positron collision data collected at the Upsilon(4S) resonance by the Belle II experiment in Tsukuba, Japan. Using two different but complementary reconstruction techniques, we found, for the first time, evidence for the B+→K+νν̄ process. At the end of my talk, I will highlight other future opportunities in B-decays with invisible signatures.
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Speaker: Michel Piat (APC-IN2P3) - Title: The Q&U Bolometric Interferometer for Cosmology (QUBIC): status and perspectives
2024-04-09 16:00 - 17:00
Research Progress Meeting
Date: April 9, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Michel Piat (APC-IN2P3)
Title: The Q&U Bolometric Interferometer for Cosmology (QUBIC): status and perspectives
Abstract: QUBIC (Q & U Bolometric Interferometer for Cosmology) is an international ground-based experiment dedicated in the measurement of the polarized fluctuations of the millimeter sky and especially the Cosmic Microwave Background (CMB). It is based on bolometric interferometry, an original detection technique which combine the immunity to systematic effects of an interferometer with the sensitivity of low temperature incoherent detectors. QUBIC is currently in commissioning in Argentina, at the Alto Chorrillos mountain site at 5000m a.s.l. near San Antonio de los Cobres, in the Salta province. After a description of the QUBIC instrument, I will present the last results of the first characterization phases with a focus on the detectors and readout system based on NbSi Transition Edge Sensors (TESs) cooled to 320mK. The perspective of spectro-imaging will also be described allowing for better foreground mitigation. This feature will soon be tested with QUBIC and could represent a significant breakthrough in CMB polarimetry.

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Speaker: Joshua Combes (JILA) - Title: Game of Qubits: winter is coming
2024-04-04 16:00 - 17:00
Research Progress Meeting
Date: April 4, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Joshua Combes (JILA)
Title: Game of Qubits: winter is coming
Abstract: The ‘Quantum Winter’ is a term that paints a scenario where the progress in quantum computing might significantly slow down, accompanied by a decrease in both public and private investment, and mounting skepticism regarding the field’s potential and future accomplishments. This concept echoes the historical ‘AI Winters,’ periods of contraction in artificial intelligence research. In this presentation, I will first evaluate our current milestones in quantum hardware development, setting the stage for an understanding of why there’s a growing concern about an impending Quantum Winter. Following this, I’ll share my forecasts, pinpointing specific years when we might anticipate this cooldown to manifest. To conclude, I’ll turn the lens inward, contemplating proactive strategies and responses we, as a research community, should consider to navigate and possibly mitigate the impact of this predicted quantum chill. This talk aims not only to forecast but to fortify our resolve in advancing quantum computing through potential adversities.
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