LBNL Physics Division Research Progress Meetings

Speaker: Joshua Batson (Anthropic AI) - Title: More is Different: Generalization in Large (Language) Models
2023-10-19 16:00 - 17:00 UTC
Research Progress Meeting
Date: October 19, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Joshua Batson (Anthropic AI)
Title: More is Different: Generalization in Large (Language) Models

Abstract: Specialized machine learning models have been successfully applied in science and industry for decades. In recent years, a new paradigm has emerged: very large models trained on highly diverse training data have demonstrated remarkable capabilities across hundreds of tasks. Many billions of dollars have since been invested in training and deploying such models. In this talk, I will review some of these developments with a focus on the phenomenon of generalization: as models scale, what changes? What do we know about the internal functioning of these models and how that emerges during training? What does this portend for the future? I will finally speculate, with audience participation, on three potential relationships with physics: the ‘physics’ of model training, the use of models as scientific assistants, and the direct use of models to study physical phenomena.
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Speaker: Kelly Stifter (Fermilab) - Title: Leveraging quantum sensors to shine new light on searches for low-mass dark matter
2023-10-26 16:00 - 17:00
Research Progress Meeting
Date: October 26, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Kelly Stifter (Fermilab)
Title: Leveraging quantum sensors to shine new light on searches for low-mass dark matter

Abstract: While dark matter accounts for approximately 85% of the mass in the universe, its physical nature remains one of the most pressing open questions in the field of physics. Three decades of experiments have been searching for dark matter interactions over a wide range of candidate dark matter masses and all have come up empty-handed. Nevertheless, there remain large swaths of unexplored, well-motivated particle dark matter models that are currently inaccessible through existing detector technologies. One path to probe these remaining particle dark matter models is through the use of low-threshold quantum sensors. In this talk, I will review the landscape of dark matter direct detection, outline the potential role of quantum sensors in particle detection, and detail the early results from a calibration system critical to realizing these individual devices as fully-fledged experiments.
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Speakers: Career Panel (LBNL) - Title: How to land a faculty position: A panel discussion with career scientists in the physics division
2023-11-07 16:00 - 17:00
Research Progress Meeting
Date: November 7, 2023
Time: 4:00- 5:00 pm
Location: B50 Auditorium [In-Person and HYBRID]
Speakers: Career Panel
Title: How to land a faculty position: A panel discussion with career scientists in the physics division
Abstract: In this panel discussion postdocs and students will have the opportunity to ask career division members about how the faculty hiring process typically works in labs and universities and how to put together a winning faculty application. This year’s panelists will be

Natalie Roe (Associate Lab Director)
Dean Robinson (Theory)
Marjorie Shapiro (ATLAS)
Simone Ferraro (Cosmology)
Kevin Lesko (LZ)

Together they have about a century worth of experience with hiring panels, in a variety of fields and settings (universities + laboratories). Most of the time will be reserved for interactions with the audience, so bring along all your questions about finding permanent positions in academia.
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Speaker: Aleksandra Kusiak (Columbia) - Title: Probing the Ionized Gas Thermodynamics in Distant Galaxies with the Sunyaev-Zel’dovich Effect
2023-11-14 16:00 - 17:00
Research Progress Meeting
Date: November 14, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Aleksandra Kusiak (Columbia)
Title: Probing the Ionized Gas Thermodynamics in Distant Galaxies with the Sunyaev-Zel’dovich Effect

Abstract: The Sunyaev-Zel’dovich Effect—the Doppler boost of low-energy Cosmic Microwave Background photons scattering off free electrons in galaxies and clusters in the late Universe—is an excellent probe of ionized gas residing in distant galaxies. Its two main constituents are the kinematic SZ effect (kSZ), where electrons have a non-zero line-of-sight (LOS) velocity and which probes the electron momentum, and the thermal SZ effect (tSZ), where electrons have high energies due to their temperature, and which probes the electron integrated pressure. These two effects provide complementary information necessary to constrain the thermodynamic profile of gas residing in distant galaxies, which can be further used to understand feedback processes, a necessary ingredient to describe the evolution of the large-scale structure in our Universe and galaxy formation. Both tSZ and kSZ can be measured in cross-correlation with large-scale structure, e.g., galaxies.
In this talk, I will discuss my past and ongoing measurements of the SZ-galaxy cross-correlations with unWISE galaxies, including the projected-fields kSZ. unWISE is a galaxy catalog containing over 500 million galaxies on the full sky and consists of three subsamples of mean redshifts z=0.5, 1.1, 1.5, whose halo occupation distribution I have already constrained. If time permits, I will also present my ongoing work on mitigating foregrounds in the SZ cross-correlations, particularly the Cosmic Infrared Background (CIB).
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Speaker: Roohi Dalal (Princeton) - Title: New Cosmology Constraints from the Hyper Suprime-Cam Year 3 Data Release
2023-11-21 16:00 - 17:00
Research Progress Meeting
Date: November 21, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Roohi Dalal (Princeton)
Title: New Cosmology Constraints from the Hyper Suprime-Cam Year 3 Data Release

Abstract: The Hyper Suprime-Cam (HSC) survey is the deepest present-day weak lensing experiment, going to ~26 mag with exquisite image quality. This combination of depth and image quality achieved by HSC allows us to probe cosmology using weak gravitational lensing up to high redshifts, and these analyses serve as important preparatory studies for the next generation of weak lensing surveys, particularly the Vera C. Rubin Observatory. I will discuss our constraints on cosmological parameters using weak lensing cosmic shear power spectra measured from the Year 3 shear catalog of HSC, covering 416 square degrees of the northern sky. I will describe our cosmological analysis, including the steps we take to prevent confirmation bias as well as our modeling of various systematic effects. The quantity best constrained by our analysis is the parameter S8, which describes the clumpiness of the matter distribution in the universe. From our analysis, and other weak lensing analyses with different surveys, there is a 2-3 sigma detection of a tension in the S8 measurements from weak lensing and those from the cosmic microwave background. While this could suggest that our cosmological model is incomplete, I will discuss ongoing and future work that can further shed light on this tension, including an improved modeling of baryonic feedback at small scales.

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Speaker: Lee Hagaman (University of Chicago) – Title: Investigating Short-Baseline Neutrino Anomalies Using MicroBooNE
2023-11-28 16:00 - 17:00
Research Progress Meeting
Date: November 28, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Lee Hagaman (University of Chicago)
Title: Investigating Short-Baseline Neutrino Anomalies Using MicroBooNE

Abstract: The MicroBooNE experiment is a liquid argon time projection chamber (LArTPC) in the Booster Neutrino Beam at Fermilab. One of its primary goals is to address the 4.8 sigma MiniBooNE Low Energy Excess (LEE). Leveraging the unique capabilities of LArTPC technology to identify hadronic activity and separate photon and electron showers, MicroBooNE has achieved a search for an electron neutrino excess (potentially due to a sterile neutrino), as well as a search for a single photon excess from neutral current Delta radiative decays. In this talk, we will present a comprehensive overview of these results, as well as recent advancements toward new searches for single photons and electron-positron pairs as explanations of the MiniBooNE LEE. These include a more sensitive search for Delta radiative decays, a search for coherent-like single photon production, an inclusive single photon search, and searches for electron-positron pairs from dark sector models.

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Speaker: Michael MacKenzie (Northwestern University) - Title: Searches for Charged Lepton Flavor Violation at CMS and Mu2e
2023-11-30 16:00 - 17:00
Research Progress Meeting
Date: November 30, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Michael MacKenzie (Northwestern University)
Title: Searches for Charged Lepton Flavor Violation at CMS and Mu2e

Abstract: Neutrino oscillations have shown that lepton flavor is not a conserved quantity. Charged lepton flavor violation (CLFV) is suppressed by the small neutrino masses well below what is experimentally observable, though new physics models predict higher rates of CLFV. I will discuss a current search at the CMS experiment for the CLFV decay of the Z boson, focusing on the search for Z→e µ. I will also discuss the upcoming search for CLFV µ− → e− conversion at the Mu2e experiment at FNAL. The Mu2e experiment aims to improve the sensitivity to µ− → e− conversion by a factor of 10,000. I will present the expected µ− → e− conversion sensitivity during Run 1 at Mu2e.
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Speaker: Michael Williams (University of Michigan) - Title: Searches for Particle Dark Matter with LZ and TESSERACT
2023-12-05 16:00 - 17:00
Research Progress Meeting
Date: December 5, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Michael Williams (University of Michigan)
Title: Searches for Particle Dark Matter with LZ and TESSERACT

Abstract: The search for particle dark matter is one of the primary challenges in modern physics. Direct detection experiments typically rely on measuring signals produced when dark matter particles recoil off a detector target. In this talk, I will first discuss the LUX-ZEPLIN (LZ) experiment, which uses a dual-phase xenon time projection chamber to look for WIMP dark matter that recoils off the xenon nucleus. I will discuss LZ detector construction, first WIMP search results, and limits on effective field theory (EFT) searches of dark matter. I will then discuss the search for low-mass dark matter with TESSERACT; this encompasses interactions with two types of novel, ultra-sensitive detectors – SPICE and HeRALD. Both SPICE and HeRALD use transition edge sensors (TESs) for cryogenic readout, while using different targets: polar crystals and superfluid helium-4, respectively. I will describe the development and first measurements of new Iridium-Platinum (IrPt) TESs and the commissioning of the new HeRALD detector at LBNL.

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Speaker: Gerrit Farren (Cambridge) - Title: The Atacama Cosmology Telescope: Probing the large scale structure with ACT DR6 CMB lensing and cross-correlation with unWISE
2023-12-07 16:00 - 17:00
Research Progress Meeting
Date: December 7, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Gerrit Farren (Cambridge)
Title: The Atacama Cosmology Telescope: Probing the large scale structure with ACT DR6 CMB lensing and cross-correlation with unWISE

Abstract: I will present work on probing the large scale structure of the universe using CMB lensing from the upcoming Data Release 6 of the Atacama Cosmology Telescope (ACT) and cross-correlations with galaxies from the unWISE galaxy catalog. My talk will focus on how our highly competitive constraints from CMB lensing cross-correlations can provide insight into the widely discussed “S8/sigma8 tension”. For this purpose I will briefly introduce the high fidelity CMB lensing reconstruction obtained by the ACT Collaboration and results from the analysis of the lensing auto-correlation. I will discuss results from the cross-correlation between ACT CMB lensing and unWISE galaxies, highlighting improvements to the analysis pipeline compared to previous work on the cross-correlation between Planck CMB lensing and unWISE by some of my collaborators (Krolewski et al. 2021). I will also touch on our recent work to extend such cross-correlation analyses beyond two-point correlations using the first detection of the galaxy-galaxy-CMB lensing bispectrum.
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Speaker: Christina Wang (Cal Tech) - Title: Search for New Physics with CMS and Quantum Sensors
2023-12-12 13:00 - 14:00
Research Progress Meeting
Date: December 12, 2023
Time: 1:00- 2:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Christina Wang (Cal Tech)
Title: Search for New Physics with CMS and Quantum Sensors

Abstract:
I will present two new highly complementary approaches to search for physics beyond the Standard Model. The searches are enabled by a first-of-its kind reconstruction technique to search for long-lived particles (LLPs) using the Compact Muon Solenoid (CMS) and by new advances in quantum sensing technology to search for axions.
I will first discuss a search for physics beyond the Standard Model by searching for LLPs using a novel technique to reconstruct decays of LLPs in the CMS muon detectors. The innovative LLP reconstruction technique has been shown to be sensitive to a broad range of LLP decay modes and to LLP masses below GeV. The search yields competitive sensitivity for proper lifetime from 0.1m to 1000m with the full Run2 dataset recorded at the LHC.
In the second part of the talk, I will discuss searching for axions with a low noise quantum sensor, SNSPDs (superconducting nanowire single photon detectors). The BREAD (Broadband Reflector Experiment for Axion Detection) experiment searches for axions or dark photons using a parabolic mirror to focus axion-converted photons to the SNSPDs. The SNSPDs allow us to be sensitive to 0.04 – 1 eV axions and dark photons, due to their sensitivity to 0.04 – 1 eV photons. In this talk, I will present the progress towards a first stage dark photon pilot experiment with a focus on SNSPD characterization.

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Speaker: Deion Fellers (University of Oregon) - Title: FASER’s Search for Dark Photons and Neutrinos
2023-12-14 16:00 - 17:00
Research Progress Meeting
Date: December 14, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Deion Fellers (University of Oregon)
Title: FASER’s Search for Dark Photons and Neutrinos

Abstract: FASER is an experiment at the LHC that is designed to search for light, weakly-interacting particles produced in the far-forward direction from proton-proton collisions at the ATLAS interaction point (IP1). The detector is positioned 480 m downstream of IP1 and aligned with the beam collision axis, where particles must traverse LHC magnets and approximately 100 m of rock and concrete before reaching FASER. The novel location of the experiment provides both a low background environment and a high-intensity flux of long-lived particles. This talk will provide an overview of the FASER detector and present our first physics results, where we used a dataset collected at center-of-mass energy √s =13.6 TeV in 2022, during LHC Run 3, to directly observe neutrino interactions at a particle collider experiment for the first time and also to probe previously unconstrained phase space of the dark photon with couplings ϵ∼10−5−10−4 and masses ∼10 MeV – 100 MeV.
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Speaker: Emily Perry (UCL) - Title: Towards the discovery of galactic dark matter: the LZ experiment and beyond
2023-12-19 16:00 - 17:00
Research Progress Meeting
Date: December 19, 2023
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Emily Perry (UCL)
Title: Towards the discovery of galactic dark matter: the LZ experiment and beyond

Abstract:
The discovery of the nature of dark matter is internationally recognised as one of the highest priorities in science. Its discovery would bring forward a new era in physics and astronomy, simultaneously solving the near 100 year old missing mass problem and delivering the first evidence of physics Beyond the Standard Model (BSM). Dual phase xenon (Xe) time projection chambers (TPCs) have been dominating the search for dark matter for the past 10 years. Now not only targeting WIMPs of mass > 3 GeV/c2, but due to their scalability and advanced technologies, boast world leading sensitivity to other BSM-physics and rare or exotic neutrino physics.
The LUX ZEPLIN (LZ) dark experiment operates at the Sanford Underground Research Facility in South Dakota and is the most sensitive and largest of all Xe TPCs ever constructed. In its first science run of only 60-livedays the experiment has set the world-leading constraints on the existence of WIMPs down to a mass of 9 GeV/c2. This seminar will highlight some of the key work that has led to this result with focus on some of my specific contributions. Giving an exciting glimpse of what the future holds for LZ, I will present the innovative work that is being done on the ramp up to the next science results. I will also discuss both the short and long term future of LZ and the path to an historic dark matter discovery.

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Speaker: Joseph Bramante (Queen's University) - Title: Back to the Future With High Mass Dark Matter
2024-01-18 16:00 - 17:00
Research Progress Meeting
Date: January 18, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Joseph Bramante (Queen’s University)
Title: Back to the Future With High Mass Dark Matter
Abstract: A number of theories predict that dark matter is a supermassive particle or composite state. Discovering dark matter in this high mass regime requires different approaches. I will survey recent developments, including composite dark matter that produces unique signatures in underground experiments, dark matter detectable through its fusion of nuclei in Antarctic ice, and halo substructures heating neutron stars. I will also survey certain experiments from the 80s and 90s, which still provide the best sensitivity to many varieties of high mass dark matter.
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Speaker: Philip Harris (MIT) - Title: You can observe a lot by just watching (new AI strategies for the LHC and beyond)
2024-01-25 08:00 - 17:00
Research Progress Meeting
Date: January 25, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Philip Harris (MIT)
Title: You can observe a lot by just watching (new AI strategies for the LHC and beyond)
Abstract: With large amounts of data, a Higgs boson discovery, and world-leading constraints on an enormous amount of parameters and interactions, the Large Hadron Collider has been a phenomenal tool. However, it has reached the middle of life and is going through a mid-life crisis. We venture in a new direction to show how AI approaches are allowing us to do new, unprecedented physics measurements, leading to a mysterious deviation in Higgs boson production at high momentum. Moreover, we show a new result built on contrastive learning and semi-supervised learning strategies where, through physics-motivated choices, we teach an AI to visualize many physics processes simultaneously, allowing it to solve a variety of downstream tasks in one algorithm. The implications are far-reaching, including a world-leading Higgs boson identification and new sensitive approaches in AI-based anomaly detection. Finally, we show a dedicated path for the broad adoption of AI into all aspects of data processing at the Large Hadron Collider and other experiments, including LIGO, that are leading to faster, better, unprecedented results; the kind of results we believe can revitalize an aging accelerator.
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Speaker: Mariel Pettee (LBNL) - Title: Towards a Foundation Model for Fundamental Physics
2024-02-01 16:00 - 17:00
Research Progress Meeting
Date: February 1, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Mariel Pettee (LBNL)
Title: Towards a Foundation Model for Fundamental Physics
Abstract: The launch of ChatGPT in November 2022 ignited an ongoing worldwide conversation about the possible impacts of Large Language Models (LLMs) on the way we work. There is little doubt that LLMs will significantly influence many people’s jobs: one prominent study estimated that about 20% of the US workforce could soon see about 50% of their daily tasks influenced by these models. As scientists, however, the changes in our workflows since the advent of this technology have been relatively minor.
Will this still be the case in 10 years? Could an analogous paradigm shift arise from a foundation model trained on a large amount of scientific data, transforming the way we conduct our research? If so, what can we learn from the development of other foundation models, including LLMs, in their evolution from specialists to (quasi-)generalists? In this talk, I will present some recent work representing very early potential steps towards a foundation model of fundamental physics as well as perspectives on how we should strive to shape such a model to reflect our highest priorities as scientists.
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Speaker: Lindley Winslow (MIT) - Title: The Search for GUT-Scale Axions: Really Big Magnets and Quantum Sensing
2024-02-06 16:00 - 17:00
Research Progress Meeting
Date: February 6, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Lindley Winslow (MIT)
Title: The Search for GUT-Scale Axions: Really Big Magnets and Quantum Sensing

Abstract:
The particle nature of dark matter remains one of the great open questions in physics. There is a broad category of candidates whose mass is so light that they behave more as waves than as particles. The most well-known is the axion, which has had a renaissance as a dark matter candidate as theoretical studies have improved our understanding of axion cosmology and advances in quantum sensing and cryogenics have opened new opportunities for detection. In this talk, I will focus on the search for GUT-Scale axions, the DMRadio Program and the results from the ABRACADABRA demonstrators. If time permits, I will also discuss our other R&D efforts that span from searching for primordial black holes to coupling quantum dots to SNSPDs.

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Speaker: William Coulton (Cambridge) - Title: Novel cosmological tests with precision CMB measurements
2024-02-15 16:00 - 17:00
Research Progress Meeting
Date: February 15, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: William Coulton (Cambridge)
Title: Novel cosmological tests with precision CMB measurements
Abstract: High resolution cosmic microwave background (CMB) experiments provide views of the Universe both at redshift ~1100, when the primary CMB was produced, as well as an integrated view of the Universe between then and now, through CMB secondary anisotropies. In this talk, I will show that CMB secondary anisotropies contain a wealth of cosmological information and are becoming leading cosmological probes. I will present recent measurements from the Atacama Cosmology Telescope collaboration that have mapped out several of these effects. I will then highlight some challenges for these measurements with upcoming CMB experiments, and some unique opportunities, such as tests of the fundamental properties of our Universe.
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Speaker: Clara Verges (Harvard) - Title: A new era for cosmology with current and next-generation CMB experiments
2024-02-20 16:00 - 17:00
Research Progress Meeting
Date: February 20, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Clara Verges (Harvard)
Title: A new era for cosmology with current and next-generation CMB experiments
Abstract:
Cosmology has experienced a considerable surge in the past thirty years, and is now well established as a precision science. While the standard cosmological model provides an effective description of the observed Universe, many fundamental questions remain unresolved. From shedding light on the very first fractions of seconds after the Big Bang to looking for exotic physics, the Cosmic Microwave Background continues to be a unique probe for fundamental physics. The next generation of CMB polarisation observatories, embodied by CMB-Stage 4 for ground observations, will explore this window into the Universe in an unprecedented way, enabling breakthrough science. I will review how current experiments such as the BICEP/Keck telescopes pave the way for this next stage, by developing efficient technologies and observing strategies, and by sharpening constraints on theoretical models. I will then discuss the scientific and technological challenges that the CMB community must meet to ensure the success of future experiments.

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Speaker: Zhen Liu (University of Minnesota) - Title: The Next Leap: Physics Landscape of Future Colliders
2024-02-22 16:00 - 17:00
Research Progress Meeting
Date: February 22, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Zhen Liu (University of Minnesota)
Title: The Next Leap: Physics Landscape of Future Colliders
Abstract: The future direction of High Energy Physics (HEP) is a critical topic, especially considering the large scale and extensive preparation required for upcoming projects. We are at a point filled with opportunities for HEP, featuring a variety of promising paths that highlight its potential for major discoveries. As the introductory talk in our series on future colliders, this presentation aims to examine the potential of these future projects in a clear and comparative manner. I will overview the current landscape and the expected progress in high-energy physics experiments, spotlighting recent initiatives that have resulted in significant achievements in particle physics. The goal of this talk is to outline the broad possibilities that lie ahead for HEP, stressing the importance of innovative approaches necessary to advance this exciting area of science.
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Speaker: Brendan Crill (Jet Propulsion Laboratory) - Title: Sensitivity limits to cosmological constraints on early Universe physics: lessons from Planck for future measurements
2024-02-27 16:00 - 17:00
Research Progress Meeting
Date: February 27, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Brendan Crill (Jet Propulsion Laboratory)
Title: Sensitivity limits to cosmological constraints on early Universe physics: lessons from Planck for future measurements
Abstract:
The past several decades have seen enormous breakthroughs in the understanding of fundamental physics of the Universe through observations of the cosmic microwave background (CMB) and large scale structure. A synergy of rapid advances in technology, data analysis capabilities, and theory has led to an abundance of measurements, which in turn has seen the success of the Lambda-CDM model seeded by early-Universe inflation. This theory explains observations very few free parameters has emerged at explaining the observed structure of the universe.
Further refinements to this model and further characterization of observables in the CMB are a high priority for a deeper understanding of the nature of the physics of inflation and the evolution of structure across cosmic time. This will come about through measurements of non-Gaussianity, lensing, and the imprint of tensor modes in large-scale CMB polarization among other observables.
To achieve these refinements, projects have focused on improvements in raw sensitivity via new and more powerful detectors arrays with vastly more elements.
However, the success of earlier measurements has only come about through understanding and correction of systematic errors, understanding astrophysical foregrounds: more powerful instruments with better sensitivity are likely to uncover new challenges.
Here I describe lessons learned from the Planck mission at handling unforeseen instrumental and observational challenges and discuss prospects for fulfilling the sensitivity promise offered by large-scale structure projects such as SPHEREx and future CMB measurements.

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Speaker: Petra Merkel (Fermilab) - Title: Detectors for Future Colliders
2024-02-29 16:00 - 17:00
Research Progress Meeting
Date: February 29, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Petra Merkel (Fermilab)
Title: Detectors for Future Colliders
Abstract: I will present detector capabilities that need to be developed in order to address physics requirements at future collider experiments. In addition to laying out common detector technologies that will be useful at various collider experiments, I will also summarize differences and special requirements at the different collider options. Furthermore, I will give a brief overview of the state of the art of the R&D in some of the most crucial areas where technology development is needed in detector instrumentation.
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Speaker: Roy Aleksan (CEA-Saclay) - Title: Status of the Future Circular Collider (FCC)
2024-03-05 16:00 - 17:00
Research Progress Meeting
Date: March 5, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Roy Aleksan (CEA-Saclay)
Title: Status of the Future Circular Collider (FCC)
Abstract:
While the LHC is continuing its outstanding program, one needs to decide what the next large accelerator project in particle physics will be. There is a general global consensus that an e+e- collider is the next priority. In accordance with the 2020 European Strategy Update, the technical and financial feasibility of a circular high energy hadron collider at CERN with a centre-of-mass energy of at least 100 TeV and with an electron-positron Higgs and electroweak factory as a possible first stage has been launched in Europe. In the present talk, we shall discuss the status of this endeavor including the physics motivation, the corresponding technical implications for the detectors as well as the status of the study of the accelerator complex with special emphasis on the e+e- collider.

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Speaker: Cameron Geddes (LBL Accelerator Division) - Title: Accelerators for Future Colliders
2024-03-07 16:00 - 17:00
Research Progress Meeting
Date: March 7, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Cameron Geddes (LBL Accelerator Division)
Title: Accelerators for Future Colliders
Abstract: Particle physics motivates next generations of colliders ranging from a fraction of a TeV for precision Higgs physics to the 10 TeV parton Center of Mass (pCM) scale for both broad new physics and deep characterization of the Higgs sector. Designs for Higgs factory colliders are being formalized with the aim of a project late in the decade. The 10 TeV pCm range will place radical new demands on accelerator capability, efficiency, and cost. At the same time, accelerator science is advancing rapidly with a set of new technologies under development that make it feasible to address this frontier. These technologies, including high field magnets for proton machines, muon colliders incorporating cooling, and high gradient linear wakefield lepton colliders all require development in order to allow us to make a confident, informed decision on the path forward. These colliders, a combination of general and targeted R&D, and interactions with the detector and particle physics community to develop them will be discussed.
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Speaker: Colin Hill (Columbia) - Title: Uncovering Physics Beyond the Standard Model in the Cosmic Microwave Background
2024-03-12 16:00 - 17:00
Research Progress Meeting
Date: March 12, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Colin Hill (Columbia)
Title: Uncovering Physics Beyond the Standard Model in the Cosmic Microwave Background
Abstract:
The cosmic microwave background (CMB) anisotropy remains the cleanest, most powerful probe of fundamental physics in the cosmos. Measurements of the small-scale CMB temperature and polarization fields are set to undergo transformative improvements in the coming decade, culminating in the CMB-S4 experiment, which will open new windows into physics beyond the standard models (BSM) of particle physics and cosmology. I will first discuss my ongoing work in the Atacama Cosmology Telescope collaboration focused on cosmological parameter constraints from high-resolution CMB power spectra, with a particular emphasis on constraining BSM physics operating just prior to recombination, including new relativistic particles and new pseudo-scalar fields. I will describe high-precision end-to-end tests of our entire analysis pipeline on realistic, non-Gaussian sky simulations containing all relevant Galactic and extragalactic foregrounds, tightly coupled to a detailed instrument model. I will then turn to novel searches for BSM physics in CMB secondary anisotropies, as could be imprinted by the screening of CMB photons by massive dark photons or axion-like particles. I will show the first results of searches for these signals in CMB data, enabled by my group’s state-of-the-art needlet internal linear combination code. Finally, I will discuss new analysis methodologies for more optimally cleaning non-Gaussian foregrounds in CMB maps, with applications to both primordial B-mode searches and small-scale secondary anisotropy measurements. I will conclude with a look ahead to the prospects for BSM physics from the Simons Observatory and CMB-S4.

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Speaker: Matthias Hohenberger (LLNL) - Title: Demonstrating fusion ignition in the laboratory for the first time
2024-03-14 16:00 - 17:00
Research Progress Meeting
Date: March 14, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Matthias Hohenberger (LLNL)
Title: Demonstrating fusion ignition in the laboratory for the first time
Abstract: At approximately 1 am on December 5th, 2022, a fusion experiment at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory achieved, for the first time, a target gain exceeding 1. By imploding a small capsule containing deuterium-tritium fuel with 2.05 MJ of laser light, the resulting fusion reactions released a total energy of 3.15 MJ of nuclear fusion yield, thus exceeding the initial input energy. This was the first time for a laboratory experiment to meet the 1997 definition by the National Academy of Sciences of fusion ignition, an accomplishment six decades in the making. It is the result of focused work by a multi-lab team and required significant advances in high-energy-density physics, as well as laser, target, and diagnostics capabilities. This talk will discuss this momentous result, the steps that went into achieving it, and the implications of this achievement for Inertial Fusion Energy.
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Speaker: Christian Reichardt (Melbourne) - Title: Observing the oldest light in the Universe from the South Pole: Gravitational waves, Neutrinos and more!
2024-03-19 16:00 - 17:00
Research Progress Meeting
Date: March 19, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Christian Reichardt (Melbourne)
Title: Observing the oldest light in the Universe from the South Pole: Gravitational waves, Neutrinos and more!
Abstract:
The cosmic microwave background (CMB) radiation is the oldest light we can see. Since it bears the imprint of the universe just after the Big Bang (at a mere 0.003% of the universe’s age today), observations of the CMB are a crucial tool in our quest to understand how the Universe began and what its future holds. The South Pole is one of the best sites on Earth for these observations, and is the home of the South Pole Telescope (as well as CMB-S4 in the future). In this talk, I will present the latest CMB power spectra measurements from the SPT-3G instrument on the South Pole Telescope, and the resulting constraints on cosmology.

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Speaker: Tom Shutt (SLAC) - Title: GammaTPC: A novel next generation Compton telescope
2024-03-21 16:00 - 17:00
Research Progress Meeting
Date: March 21, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Tom Shutt (SLAC)
Title: GammaTPC: A novel next generation Compton telescope
Abstract: I will talk about GammaTPC, a new instrument concept for measuring astrophysical gamma rays in the MeV energy range. This part of the sky is a largely unexplored mostly due to the difficulty of measuring MeV photons, but the potential payoff is large, particularly in the upcoming era of multi-messenger transient astrophysics. GammaTPC attacks this difficulty using liquid argon time projection chamber (TPC) technology, which appears to have important advantages over several other techniques that are being pursued. A core part GammaTPC is GAMPix, a new charge readout scheme that enables fine grained readout over large area at very low power, and has other potential applications including neutrino physics. There are a few other amusing challenges to fielding a liquid noble TPC in low Earth orbit.
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Speaker: Raphael Flauger (UC San Diego) - Title: Deciphering the Beginning
2024-03-26 16:00 - 17:00
Research Progress Meeting
Date: March 26, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Raphael Flauger (UC San Diego)
Title: Deciphering the Beginning
Abstract:
The cosmic microwave background (CMB) contains a wealth of information about cosmology as well as high-energy physics. It tells us about the composition and geometry of the universe, the properties of neutrinos, dark matter, and even the conditions in our universe long before the cosmic microwave background was emitted. After a brief introduction, I will discuss what we may hope to learn about the very early universe from upcoming CMB experiments that search for the imprint of primordial gravitational waves. One of the key challenges of this endeavor is the polarized emission from our galaxy. I will discuss our recent efforts to model and better understand the emission with the help of MHD simulations.

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Speaker: Chiara Salemi (SLAC) - Title: Seeing the invisible: the search for axion dark matter
2024-03-28 16:00 - 17:00
Research Progress Meeting
Date: March 28, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Chiara Salemi (SLAC)
Title: Seeing the invisible: the search for axion dark matter
Abstract: The presence of dark matter provides some of the most persuasive evidence for the existence of physics beyond the Standard Model. One compelling dark matter candidate is the axion, a light boson that was originally postulated as a solution to another outstanding issue, the strong CP problem in QCD. This talk covers two experimental programs to search for axion dark matter with advanced quantum sensors: DMRadio and BREAD. DMRadio searches for low-mass (long-wavelength) axions using a lumped-element detection method, while BREAD searches for relatively high-mass (short-wavelength) axions using a reflector. I will discuss the status and upcoming plans for these two programs, with a focus on the quantum sensors that enable these kinds of searches.
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Speaker: Boryana Hadzhiyska (UC Berkeley) - Title: Solving big-scale problems with small-scale models in the era of CMB-S4
2024-04-02 16:00 - 17:00
Research Progress Meeting
Date: April 2, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Boryana Hadzhiyska (UC Berkeley)
Title: Solving big-scale problems with small-scale models in the era of CMB-S4
Abstract: In this talk, I will focus on some of the new opportunities and new challenges that CMB-S4, the next-generation cosmic microwave background (CMB) experiment, presents, and I will offer a viable path forward to meeting and exceeding the goals we have set up for it. The CMB has played a huge role in shaping our understanding of the history, evolution and contents of our Universe. From our observations of the CMB, we have attained a good grasp of about 13.8 billion years of cosmic history, but our direct and indirect observations are limited to a much smaller range in energy scale, which leaves unresolved some of the biggest puzzles such as the mechanism that seeded the primordial fluctuations and the nature of the dark sector. I will discuss how we can leverage observations of the CMB to learn about these much earlier periods of cosmic history and also, how the CMB provides complementary probes of the lower-redshift universe. On large scales, the B-mode polarization signal can reveal the origin of primordial fluctuations, whereas the small-scale signal holds information about the presence of non-standard light relics and the sum of the neutrino masses. However, measuring the primordial signal is a non-trivial task, as on its way to us, the signal has picked up contributions from lensing and astrophysical sources, known as foregrounds. The best way to design accurate approaches for mitigating these foregrounds is via realistic all-sky simulations. I will present new techniques for painting foregrounds onto large-volume simulations, using physically motivated models that close the loop between simulations and observations. In addition, I will discuss ways of optimizing the CMB lensing reconstruction techniques, which is crucial for improving our constraints on primordial quantities such as the number of light relics and the tensor-to-scalar ratio as well as the sum of neutrino masses. Finally, I will argue that synergies between CMB secondaries and large-scale structure surveys can place tight constraints on cosmology and astrophysics. The measurement precision of CMB-S4 will be unmatched, but in order to make the most out of it, we need a big step-up in our analysis and theory tools, including the development of realistic all-sky simulations as well as techniques for optimal extraction of the small-scale cosmological signal.

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