Barbara Jacak (LBNL/UCB) "The Mysteries of QCD Matter - Hot and Cold"
2019-08-01 16:00 - 17:00 (America/Los_Angeles) | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
QCD predicts a phase transition to quark gluon plasma. This plasma is now produced regularly in collisions of heavy nuclei at both RHIC and the LHC, and it exhibits remarkable properties. Its vanishingly small shear viscosity to entropy density ratio means that it ﬂows essentially without internal friction, making it one of the most “perfect” liquids known. Quark gluon plasma is also very opaque to transiting strongly interacting particles. Determining the transport properties of quark gluon plasma is a key goal of current research, and jets of hadrons offer a promising probe. Howevere, it remains a mystery how this plasma emerges from cold, dense gluonic matter deep inside nuclei within 1 fm/c. Furthermore, properties of the cold QCD matter deep inside nuclei are unknown. I will discuss how a future electron-ion collider can help address these questions.

Bruno Lenzi (IRFU, Saclay France)"Recent results of the CMS experiment at LHC"
2019-08-06 16:00 - 17:00 (America/Los_Angeles) | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The CMS experiment has analyzed up to 140 fb-1 of pp collisions delivered by the LHC at 13 TeV. This data has allowed for improved precision in several aspects of Higgs-boson and electroweak physics and pushed the frontiers on searches for new resonances, long-lived particles and other phenomena. I will highlight some of the recent CMS results and prospects for the High-Luminosity running phase.

Susan Hubbard (ESA, LBNL) "Imaging Watershed Behavior & Overview of the Earth and Environmental Sciences Area"
2019-08-29 16:00 - 17:00 (America/Los_Angeles) | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
Quantifying how terrestrial systems respond to climate change and other perturbations is challenging due to the complexity of associated processes that occur from bedrock-to-canopy and from genome to watershed scales. This presentation will describe the development of several new approaches to help bridge these compartments and scales through integrating disparate geophysical, hydrological, geochemical and microbial datasets. A brief overview of the Earth and Environmental Sciences Area will first be provided to motivate the technical presentation. The presentation will subsequently describe the use of new geophysical characterization approaches in an Arctic tundra ecosystem, where increasing temperatures are thawing the permafrost, potentially leading to significantly increased production of greenhouse gasses. The development and testing of new methods to quantify the structure and function of a mountainous watershed in the Upper Colorado River Basin, where droughts and early snowmelt may influence downgradient water availability and water quality, will then be presented. The recent advances are leading to insights about how these systems function and respond to perturbations – from local scales where native processes occur toward watershed scales that are relevant for managing natural resources.

David Schlegel (LBNL) "TBA"
2019-09-05 16:00 - 17:00 (America/Los_Angeles) | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:

Beate Heinemann (DESY) "European Strategy for Particle Physics Update 2020: Status and Prospects"
2019-09-19 16:00 - 17:00 (America/Los_Angeles) | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
At present a process is ongoing in Europe to update the European Strategy of Particle Physics with respect to the previous update from May 2013. The process was started last year and is expected to end in May 2020. Major discussions of the scientific prospects of a wide variety of future projects took place during a symposium in Granada/Spain. In this talk I will explain the process and try to highlight the scientific opportunities discussed.

Patrick de Perio (Triumf) " CP Violation in Neutrino Oscillations with Hyper-Kamiokande
2019-10-01 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract: We live in a matter dominated world, so where did all the antimatter go? The Hyper-Kamiokande (Hyper-K) experiment in Japan is trying to detect charge-parity violation (CPV) in neutrino oscillation, which could help explain this phenomenon. As the successor of the T2K experiment, Hyper-K produces a beam of neutrinos or antineutrinos directed towards a far detector 295 km away, which is about 8 times bigger than the current far detector, Super-Kamiokande, a water Cherenkov detector. With an expected statistical uncertainty of 3% for both neutrinos and antineutrinos, Hyper-K aims to tease out the small neutrino/antineutrino oscillation difference. In this talk, I will discuss our efforts to control systematic errors at an unprecedented level, arising from 1) neutrino beam production, 2) neutrino interaction modeling, and 3) water Cherenkov detector calibration.

David Shih (Rutgers/LBNL) "Searching for the Unexpected at the LHC with Unsupervised Machine Learning"
2019-10-22 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
Conventional methods for searching for new physics at the LHC have mostly been “top-down”: starting from a specific model, searches are designed and optimized to have the best sensitivity to that model. Despite hundreds of conventional new physics searches at the LHC, none have turned up any hint of new physics. Maybe it’s time to admit that we don’t know what we’re looking for.
Breakthroughs in modern deep learning have the potential to revolutionize how we search for new physics at the LHC. In particular, techniques borrowed from unsupervised machine learning could enable us to search for new physics in a largely model-agnostic way. In this talk I will review some promising recent proposals in this direction. These proposed search strategies could complement more conventional methods by finding surprising signals that were not anticipated by any model, ensuring that we leave no stone unturned in the hunt for new physics at the LHC.

Koji Terashi (CERN) " Quantum Computing and Possible Application to High-Energy Physics"
2019-10-31 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
High-energy frontier in particle physics is going to enter into an era of precision studies after Run 3 at the LHC, with the increase of proton luminosity and upgraded detectors. This will pose a significant challenge to the event reconstruction and data analysis, where one has to look for (tiny) hints of new physics in a huge amount of collected data. Over the last few years quantum computing, in particular the hardware systems with superconducting qubits, has grown significantly, making a quantum computer with order of 50-100 qubits, called NISQ device, nearly in hand. This motivates an exploration of this new technology in high energy physics (HEP) experiments, aiming to identify interesting application of quantum algorithms to data analysis. In this talk, I will discuss about possible HEP applications of quantum computing and current status of those studies.

Reserved
2019-11-05 16:00 - 17:00, 2019-11-07 16:00 - 17:00, 2019-11-12 16:00 - 17:00, 2019-11-14 16:00 - 17:00, 2019-11-19 16:00 - 17:00, 2019-11-26 16:00 - 17:00, 2019-11-28 16:00 - 17:00, 2019-12-19 16:00 - 17:00 UTC and 4 more dates | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132

Zhaodi Pan (U. Chicago) "Instrument and science for the SPT-3G cosmic microwave background receiver"
2019-11-21 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

SPT-3G is a third-generation camera for the 10-meter diameter South Pole Telescope (SPT), which is designed to measure the cosmic microwave background (CMB). To achieve a high mapping speed, we have developed a new multichroic receiver with a total of 16,000 polarization-sensitive detectors. SPT-3G began a 6-year 1500 square degree survey in February 2018, which will produce measurements of CMB temperature and polarization anisotropies with an unprecedented combination of angular resolution and sensitivity. In this talk, I will summarize the instrument status and highlight the development of the most compact millimeter-wavelength Fourier transform spectrometer, which was used for SPT-3G and is also a prototype for the proposed PIXIE satellite. I will also discuss the science goals and current data analyses, with a focus on the gravitational lensing analysis using SPT-3G’s first-year data.

Tommaso Ghigna (Oxford U.) "The quest for CMB B-modes and the challenge of controlling systematic effects"
2019-12-03 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The Cosmic Microwave Background has played a central role for cosmology in the past few decades. From the very first detection of its temperature more than 50 years ago to the measurement of the temperature anisotropy, every step contributed to advancing our understanding of the fundamental laws that govern our Universe. One of the most ambitious targets of current and future experiments is the detection of the primordial polarized B-mode signal. This signal is a tracer of inflation and it is expected to be most visible at large angular scales.
I will review the current status of the search for B-modes focusing on one of the main challenges: instrumental systematic effects and strategies to keep them under control. In particular I will discuss the impact of band-pass uncertainty in the presence of Galactic foregrounds. I will describe a simulation procedure developed to study the induced bias into CMB polarization maps, and the recovered tensor-to-scalar ratio parameter. I will describe the connection between the simulation results and the instrumental parameters for a representative space mission, and define requirements to minimize the effect. Furthermore, I will introduce our current plan to develop a testbed, which we can use to address multiple systematic effects without waiting for the fully assembled instrument.
The required sensitivity for a definitive measurement of the B-mode signal is extremely challenging, and focal planes of experiments are growing in size to increase the optical throughput in order to meet the requirements. This will require extra efforts in designing, fabricating, and testing all telescope components; only through meticulous knowledge of the instrument and all its sub-systems, as well as a careful calibration, we will be able to reach this ambitious goal.

Peter Timbie (UW-Madison) "21cm Intensity Mapping: A New Cosmological Tool?"
2019-12-05 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
The 21 cm line from neutral hydrogen gas has many useful properties for mapping large volumes of the cosmos. These maps will give us a view of the Universe when the first luminous objects formed through gravity – the Cosmic Dawn and the Epoch of Reionization, and later, the post-Reionization Universe. They may even allow us to map the epoch before these luminous objects, the cosmic dark ages. The large volumes of these maps promise dramatic improvements in estimation of cosmological parameters. Data is flowing now from a new generation of radio telescopes optimized for this task. Unfortunately, the main challenge for all of them is that the astrophysical radio foregrounds are ~10,000 times brighter than the expected hydrogen signal. In this talk I will focus on current and planned efforts to use the new technique of` ‘hydrogen intensity mapping’ to make tomographic maps of the post-Reionization universe. In particular, I will describe the first measurements from an instrument in China, called the Tianlai (‘Cosmic Sound’) Pathfinder.

Jelle Aalbers (Stockholm U) "XENON1T: When All Other Lights Go Out"
2019-12-10 16:00 - 17:00 UTC | 50B-4205
Abstract:
Direct detection experiments create the most radioactively quiet spots on earth, to reveal collisions between dark and ordinary matter. XENON1T, the most sensitive such experiment currently, will soon be succeeded by LZ and XENONnT. This talk highlights XENON1T’s recent light dark matter search results, and modern analysis techniques — full online processing, and tensorflow-based profile likelihoods — to boost the physics reach of future direct detection experiments and other rare-event searches.

Qing Shilo Xia (Yale) "Hunting for neutrinoless double beta decay with liquid xenon detectors"
2019-12-12 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

Liquid xenon (LXe) is employed in a number of current and future detectors for rare event searches. In this talk, I will present the latest results from EXO-200, which searched for neutrinoless double beta decay (0υββ) in Xe-136 between 2011 and 2018. I will also present a measurement of the absolute scintillation and ionization response generated by MeV energy gamma sources over a range of electric fields in EXO-200. These measurements are useful for simulating the performance of future 0υββ detectors employing LXe, such as nEXO, which is a next generation 0υββ experiment using Xe-136 aiming to reach a half-life sensitivity ~10^28 years. nEXO will require ultra-low radioactivity, high-speed cabling to carry digital signals from in-LXe electronics. I will describe the development of high-bandwidth digital cable prototypes with sufficiently low radioactivity for use in the experiment. While designed specifically for nEXO, the demonstration of radiopure high-bandwidth cabling and interconnection techniques is relevant for many next-generation rare-event searches with large channel counts and high-speed digital electronics.

Sumit Dahal (Johns Hopkins U) "The Cosmology Large Angular Scale Surveyor: Detector Design and Performance"
2019-12-17 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The Cosmology Large Angular Scale Surveyor (CLASS) aims to characterize the primordial gravitational waves at the level of tensor-to-scalar ratio of 0.01, and make a cosmic-variance-limited measurement of the optical depth to reionization. CLASS is an array of four telescopes that surveys 70% of the microwave sky from the Atacama Desert at 40, 90, 150, and 220 GHz frequency bands. A unique combination of large sky coverage, rapid front-end polarization modulator, broad frequency coverage, and background-limited detectors enables CLASS to characterize the B-mode and E-mode power spectra on both the reionization and recombination scales. The detector arrays for all four CLASS telescopes contain smooth-walled feedhorns that couple to transition-edge sensor bolometers through planar orthomode transducers fabricated on mono-crystalline silicon. In this talk, I will give an overview of the design and performance of the CLASS detectors and provide an update on the current status of CLASS telescopes.

Hanna Herde (Brandeis U.) "Measuring the Mass of the Higgs Boson in the Four-Lepton Final State with the ATLAS Detector"
2020-01-07 16:00 - 17:00 UTC | 50B-4205
Abstract:
The Higgs boson mass determines its couplings to every other known particle – and it is a free parameter of the Standard Model of Particle Physics. Understanding the Higgs’ connections with the rest of the universe requires measuring its mass experimentally. This talk presents the mass measurement in the four-lepton final state with the ATLAS detector using the full LHC Run 2 proton-proton dataset of 139 fb at sqrt{s}=13 TeV. It will particularly emphasize the role of the detector and include a look at ATLAS’ future in the High Luminosity era – the Phase II Inner Tracker upgrade.

Zhi Zheng (U. Michigan) "Physics with the same-sign dilepton and multilepton events"
2020-01-09 16:00 - 17:00 UTC | 50B-4205
Abstract:
Despite of the discovery of a Higgs-like particle in 2012, there are still many unanswered questions. Studying events with the same-sign dilepton and multilepton (SSML) may help to gain insight into those questions. In this presentation, I will give an overview of physics and challenges related to the analyses of SSML events, focusing on the three analyses I worked on, namely, search for beyond standard model physics, studies of ttH and ttW production and search for four-top production with the ATLAS detector.

Marjon Moulai (MIT) "Unstable Sterile Neutrinos in IceCube and Beyond
2020-01-14 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Long-standing anomalies in short-baseline neutrino oscillation experiments suggest the existence of a new particle: the sterile neutrino. Unlike other neutrinos, sterile neutrinos do not interact via the weak nuclear force. Global fits to experimental data find a significant preference for a 3+1 sterile neutrino model, which introduces a fourth, heavier mass eigenstate, over the Standard Model with three massive neutrinos. However, disagreement between the preferred parameter regions in the appearance and disappearance datasets suggest that something beyond the 3+1 model is needed. In this talk, I will address this problem in two ways: the first is a new, unique search for sterile neutrinos, and the second is an unstable sterile neutrino model. IceCube, a gigaton ice-Cherenkov detector, is uniquely sensitive to a signature of sterile neutrinos that occurs for neutrinos traversing the earth at TeV energies. I will present the new 3+1 sterile neutrino search result from IceCube using eight years of data. Then I will discuss a sterile neutrino model involving neutrino decay. I will present: the phenomenology of this model in the case of IceCube; the result of incorporating IceCube data into recent global fits; and finally, the status of an eight-year search for unstable sterile neutrinos in IceCube.

Daniel Joseph Antrim (UCI) "It Takes Two to Lambda: A New Dilepton Channel for the Search for Higgs Boson Pairs and a Pair of New Small Wheels for the Upgrade of the ATLAS Detector at CERN"
2020-01-16 16:00 - 17:00 UTC | INPA Common Room (50-5026), 50-5026
Abstract:
The rich program of study opened up by the discovery of a 125 GeV boson in 2012 so far leads us to consider this particle to be the Higgs boson as predicted by the Standard Model (SM) of particle physics, the particle famously responsible for providing elementary particles their masses. To be sure that this is the case, the last-remaining fundamental parameter of the SM — the Higgs self-coupling parameter, “lambda” — will have to be measured and checked for consistency with SM-prediction. In the SM, the parameter lambda gives structure to the Higgs vacuum and is therefore fundamental to our understanding of electroweak physics and symmetry breaking that is paramount to our understanding of the Universe. Measurement of lambda at the LHC will proceed via the study of ultra-rare pp collision events in which Higgs boson pairs (HH) are produced. If the LHC is to have a chance at making meaningful statements about lambda, all avenues of study of HH must be sought out. In this talk I will therefore discuss a promising brand new channel in the search for Higgs boson pairs that I have developed and introduced over the past several years using the ATLAS detector at CERN. Additionally, with the foreseen increases in pp collision intensities over the next decades, the ATLAS detector will have to be upgraded if the physics program is to remain successful. This is especially true if we wish to have any hope of observing HH events. With this in mind, I will also touch upon my involvement in the on-going upgrade of the forward muon system of the ATLAS detector, the so-called “New Small Wheel” (NSW) Upgrade, which comprises an upgrade of over 60% of ATLAS’ muon spectrometer coverage as well as being the largest on-going upgrade of any of the LHC experiments.
