LBNL Physics Division Research Progress Meetings

Reserved
2020-01-02 16:00 - 17:00, 2020-02-06 16:00 - 17:00 UTC | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132

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 | 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 | 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 | 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 | 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.

Damian Goeldi (Carleton U) "Enhancing the Physics Reach of the DUNE far Detector"
2020-01-21 16:00 - 17:00 | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

DUNE is a planned long-baseline neutrino oscillation experiment measuring μ disappearance and e appearance in an accelerator μ beam (arXiv:1601.05471). Its primary goals are measuring CP violation in the lepton sector, determining the ordering of the three neutrino masses, and precision tests of the three-flavour neutrino oscillation paradigm. Furthermore, DUNE aims to investigate proton decay, and the neutrino flux from the core-collapse of a potential supernova within our galaxy. Finally, it has recently been proposed (DOI:10.1103/PhysRevLett.123.131803) that an upgraded far detector design could enable DUNE to shed light on the current 2 discrepancy between reactor and solar neutrino oscillation measurements. Liquid argon time projection chambers (LArTPCs) were chosen as primary detectors for the DUNE near and far detector complexes due to their excellent tracking and calorimetry performance. The far detector complex will consist of four multi-kt detectors, whose baseline design is of semi-monolithic nature (arXiv:1807.10327), segmenting each module along the drift axis into multiple TPCs. In contrast a near detector LAr component needs to be fully segmented due to the high event rates present there. This motivated the development of ArgonCube, a fully modular TPC concept, alleviating high-voltage requirements, reducing optical pile-up, and providing ambiguity-free tracking and calorimetry by means of a pixelated charge readout. While near detector development is well on track, we have recently made the case for an ArgonCube far detector design (arXiv:1908.10956). Full segmentation would alleviate high-voltage requirements drastically. Combined with the pixelated charge readout eliminating bulky wire frames, the sensitive volume could be increased significantly. A pixelated charge readout providing true 3D tracking free from ambiguity would simplify event reconstruction. Reconstruction efficiency would no longer depend on the incident angle of an interaction, enhancing sensitivity to isotropic events, such as proton decay, solar, and supernova neutrinos. This talk will first introduce the ArgonCube concept, and show how it addresses the DUNE near detector challenges. I will then focus on the potential of an ArgonCube far detector to enhance DUNE’s capabilities in regards to its secondary physics goals, as well as the changes required compared to the near detector design.

Special RPM | Gregor Kasieczka (Hamburg U) "Faster, Deeper, Stronger: Machines Learn Particle Physics
2020-01-22 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Many experimental results from both particle and astrophysics hint that the Standard Model (SM) of particle physics cannot be a complete theory of Nature. However, in its first years of operation, the Large Hadron Collider at CERN was very successful in excluding large regions of parameter space for potential models beyond the SM. We present how deep learning can be used to search for deviations from the SM in a model independent way. Beyond searching for new physics, we explore ways to increase the robustness and understanding of network decisions and show how generative models can speed up simulations.

Michal Zamkovsky (CERN) "New result on K+→π+vv ̅ from the NA62 experiment"
2020-01-23 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:

The decay K+→π+vv ̅, with a very precisely predicted branching ratio of less than 10exp(-10), is one of the best candidates to reveal indirect effects of new physics at the highest mass scales. The NA62 experiment at the CERN SPS is designed to measure the branching ratio of the K+→π+vv ̅ with a decay-in-flight technique. NA62 took data so far in 2016-2018. Statistics collected in 2016 allowed NA62 to reach the Standard Model sensitivity for K+→π+vv ̅, entering the domain of 10-10 single event sensitivity and showing the proof of principle of the experiment. Thanks to the statistics collected in 2017, NA62 surpasses the present best sensitivity. The analysis strategy is reviewed and the preliminary result from the 2017 data set is presented.

Vivek Singh (LBNL) "New results for Neutrinoless Double-Beta Decay search in 130Te with CUORE "
2020-01-28 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The CUORE experiment — with a detector array comprising 988 cube-shaped radiopure natTeO2 crystals — is the world’s largest and most sensitive low temperature calorimetric search for neutrinoless double beta (0νββ) in 130Te. We completed the construction of the experiment in August 2016 and started science data taking in Spring 2017. Since our first results from Fall 2017, we have quadrupled our exposure and have bettered the sensitivity for the $0
ubetabeta$ search using analysis improvements. In this talk, I will delve into the data taking campaign, analysis techniques, and discuss the recent physics results from the full CUORE datasets accumulated over the last two years.

Huilin Qu (UCSB) "Search for the Higgs Boson Decaying to Charm Quarks with the CMS Experiment"
2020-01-30 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

After the discovery of the Higgs boson at the LHC, thoroughly studying the properties of the Higgs boson has become one of the top priorities of the LHC physics program. Measurement of the decay of the Higgs boson to charm quarks provides a direct probe of the Higgs coupling to second-generation quarks, therefore it is crucial for understanding the structure of Yukawa couplings. However, such a measurement is extremely challenging at the LHC due to large backgrounds. Recently, a search for the Higgs boson decaying to charm quarks has been performed in the CMS experiment. Novel approaches and advanced machine learning-based techniques for the Higgs boson reconstruction and charm quark identification are adopted in this analysis, leading to significantly improved results compared to previous experimental searches.

Matthew Solt (Stanford U) "The Heavy Photon Search Experiment
2020-02-04 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

The Heavy Photon Search (HPS) experiment is a fixed target experiment at Jefferson Lab searching for a new dark-force mediator called a heavy photon (or dark photon or A’). A heavy photon is a hypothetical U(1) vector boson that couples to the Standard Model photon through kinetic mixing, and thus can be produced in a process analogous to bremsstrahlung by an electron beam incident on a dense target. If kinematically allowed, subsequent decays into e+e- pairs can be detected by the HPS detector – a compact, large acceptance spectrometer consisting of a silicon vertex tracker and lead-tungstate electromagnetic calorimeter. For large couplings, heavy photons would appear as a resonance peak in the invariant mass spectrum on top of a large QED background. For sufficiently small couplings, heavy photons are long-lived and would appear as decay vertices displaced from the target beyond a prompt QED background. In this talk, I will discuss the motivation for heavy photons and the HPS detector. I will then focus on the displaced vertex analysis and discuss the results from our engineering in 2015 (1.06 GeV beam energy), the ongoing analysis of the engineering run in 2016 (2.3 GeV beam energy), and finally the upgrades and commissioning of our most recent physics run in 2019 (4.55 GeV beam energy).

Callum Wilkinson (Albert Einstein Center for Fundamental Physics) "Precision neutrino oscillation physics and DUNE "
2020-02-11 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Neutrino oscillations have been established as an energy and distance dependent phenomena, beyond the Standard Model of Particle Physics. However, a number of key questions remain, which have implications for our understanding of the origin and development of our Universe. The Deep Underground Neutrino Experiment (DUNE), which is currently in the planning stage, has the potential to answer these outstanding questions and make measurements of the other parameters with unprecedented precision. This talk gives an overview of the DUNE sensitivity to oscillation parameters, and describes a program of research aimed at reducing systematic uncertainties, and achieving DUNE’s physics goals.

Ben Safdi (U. Michigan) "The Search for Axion Dark Matter
2020-02-13 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Dark matter is the dominant source of matter in our Universe. However, while dark matter dictates the evolution of large-scale astrophysical systems through its gravitational effects, the particle nature of dark matter is unknown. In this talk I will review the current status of the search for the particle dark matter candidate called the axion, which is both well-motivated theoretically and also relatively unexplored experimentally. I will focus specifically on new large-scale numerical simulations of axion cosmology that lead to precise predictions for (i) the axion mass that gives the correct dark matter abundance, and (ii) the structure of dark matter on small astrophysical scales. I will show that axion dark matter may be harder to detect directly in the laboratory than previously thought, given that the cosmological axions are mostly confined to compact minihalos, but that this dark matter scenario may still be detectable using radio telescope searches for axion-induced radio lines.

Heidi Schellman (Oregon State U) "Computing for the DUNE Long Baseline Neutrino Oscillation Experiment "
2020-02-18 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:

The DUNE long baseline neutrino oscillation collaboration consists of over 180 institutions from 33 countries. The experiment will consist of 4 10kT fiducial volume liquid argon TPC’s in South Dakota and a multi-system near detector at Fermilab. The far site in the Sanford Underground Laboratory is in preparation now with commissioning of the first 10kT fiducial volume Liquid Argon TPC expected over the period 2025-2028 and a long data taking run with 4 modules expected from 2029 and beyond.
An active prototyping program is already in place with a short test beam run with a 700T, 15,360 channel prototype of single-phase readout at the neutrino platform at CERN in late 2018 and tests of a similar sized dual-phase detector scheduled for mid-2019. The 2018 test beam run was a valuable live test of our computing model. The detector produced raw data at rates of up to ~2GB/s. These data were stored at full rate on tape at CERN and Fermilab and replicated at sites in the UK and Czech Republic. In total 1.8 PB of raw data were produced and reconstructed during the six week test beam run.
Baseline predictions for the full DUNE detector data, starting in the mid 2020’s are 30-60 PB of raw data per year. In contrast to traditional HEP computational problems, DUNE’s Liquid Argon TPC data consist of simple but very large (many GB) 2D data objects which share many characteristics with astrophysical images. This presents opportunities to use advances in machine learning and pattern recognition as a frontier user of High Performance Computing facilities capable of massively parallel processing.

Simon Knapen (IAS) "Soft signals at the LHC"
2020-02-20 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
The LHC is both a Higgs and B-factory, and for both particles it will deliver the largest data set for many decades to come. I will discuss a few examples of ways we can leverage this to search for beyond the Standard Model physics. Some ideas can be implemented now, while others rely on the phase II detector upgrades.

Raquel Castillo Fernandez (Fermilab) "Searching for Nu Physics with High Resolution Detectors"
2020-02-25 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

Neutrino physics aims to answer some of the most pressing questions in particle physics: why the Universe is dominated by matter, why the neutrino mass is so small and if there are more types of neutrinos. Due to the neutrino’s weakly interacting nature and the complexity of their interactions, this research requires very large detectors able to identify low energy particles. This challenge has pushed the development of new technologies, such as the liquid argon time projection chamber (LArTPC) detectors, allowing for unprecedented precision in particle reconstruction, and to expand the scientific program searching for more rare channels are present in some theories of new physics beyond the current standard model. After briefly reviewing the basis of neutrino physics, I will introduce the main principles of the LArTPC detectors and how they can help us addressing some of the most relevant questions in particle physics. I will also describe the scientific achievements and the potential of the LArTPC neutrino program in the U.S., the current short (MicroBooNE/SBN) and the future long-baseline (DUNE) neutrino experiments.

Ken Van Tilburg (NYU/IAS) "The Structure of Dark Matter on Small Scales"
2020-02-27 16:00 - 17:00 | Zoom Talk, 50A-5132, Berkeley, ca, 94720
ABSTRACT:

Halometry—mapping out the spectrum, location, and kinematics of nonluminous structures inside the Galactic halo—can be realized via effects that variable weak gravitational lensing induces on the proper motions of stars and other luminous background sources. Modern astrometric surveys provide unprecedented positional precision along with a leap in the number of cataloged objects. Astrometry thus offers a new and sensitive probe of collapsed dark matter structures over a wide mass range, from one millionth to several million solar masses. It opens up a window into the spectrum of primordial density fluctuations with very small comoving wavenumbers, scales hitherto poorly constrained.

I will outline a program of detection strategies for dark matter substructure based on time-domain weak gravitational lensing, after summarizing existing techniques and constraints. I will present first results from analyses based on Gaia’s second data release. Finally, I will show that minimal models of axion-like dark matter naturally produce dense small-scale structures which can probed by the aforementioned astrometric lensing techniques.

David Caratelli (Fermilab) "Neutrinos at Short Baselines: the MicroBooNE Experiment"
2020-03-02 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

While neutrino oscillation physics has entered an era of precision measurements, several anomalies in experiments at short baselines remain without a satisfactory answer.

The MicroBooNE experiment has been recording neutrino interactions on Fermilab’s Booster Neutrino Beam since 2015 employing a liquid argon TPC detector. This talk will present recent progress on MicroBooNE’s measurement of electron neutrinos aimed at addressing past anomalies observed by the MiniBooNE collaboration.

Finally, I will talk about how developments in the ability to use liquid argon TPC detectors in the sub-GeV regime can open new opportunities in neutrino and rare-event physics with Fermilab’s upcoming short- and long-baseline neutrino programs.

Reserved
2020-03-03 08:00 - 17:00

Richard Bonventre (LBNL) "Searching for Muon to Electron Conversion: The Mu2e Experiment at Fermilab"
2020-03-03 16:00 - 17:00 | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

The Mu2e experiment will search for the charged lepton flavor violating (CLFV) neutrino-less conversion of a negative muon into an electron in the field of a nucleus, reaching a 90% C.L. limit of 8×10^-17 on the conversion rate. This sensitivity is a four-orders of magnitude improvement over previous experiments, and allows Mu2e to probe new physics at mass scales up to 10^4 TeV, far beyond the direct reach of colliders. Mu2e is currently under construction at Fermilab, and expects to begin data taking in 2023. In this talk I will present the current status of the experiment. I will also discuss the development of Mu2e detector simulations as well as the results and impact of prototype data analyses.

Tom Melia (Kavli IPMU - Japan)“ 'CMB-ing' the Search for New Physics at Colliders"
2020-03-05 16:00 - 17:00 | 70A-3377, 70A-3377
Abstract:

The effect of dark matter and dark energy in the universe can be inferred through measurements of anisotropies in the cosmic microwave background (CMB). The quantum effect of new physics on collisions at the Large Hadron Collider can be similarly inferred through measurements of what could be considered “anisotropies” in standard model processes. But how precise can one make the analogy? For example, does it make sense to talk of a “power spectrum of the standard model”? In this talk I will show how to construct just such a power spectrum, via a solution to a long-standing problem in effective field theory, and a hidden geometry in Fermi’s Golden Rule.

Keisuke Harigaya (IAS) “ Physics beyond the standard model from Higgs Parity”
2020-03-10 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

The discovery of the Higgs boson has revealed that the quartic Higgs self-coupling becomes small at very high energy scales. Guided by this observation, I introduce Higgs Parity, which is a spontaneously broken symmetry exchanging the standard model Higgs with its parity partner. In addition to explaining the small Higgs quartic coupling, Higgs Parity can provide a dark matter candidate, solve the strong CP problem, and arise from an SO(10) grand unified gauge symmetry. I will show that the Higgs Parity symmetry breaking scale is determined by standard model parameters and predicts experimental signals such as the dark matter direct detection rate and the proton decay rate. As a result, Higgs Parity provides a tight correlation between future precision measurements of standard model parameters and these experimental signals

Ka Vang Tsang (SLAC) "Imaging Neutrinos: Machine Learning in LArTPC"
2020-03-12 16:00 - 17:00 | 50-Auditorium
Abstract:

Ever since the discovery, neutrinos have proven to be one of the most intriguing subatomic particles. In the past two decades, we have made tremendous progress in the establishment of the neutrino oscillation phenomenon. We are now able to reveal the nature using neutrinos, such as CP violation in the lepton sector, the neutrino mass hierarchy, and the possible existence of the sterile neutrinos.
Liquid argon time projection chamber (LArTPC) is a novel technology for neutrino detection because of its excellent imaging capability of charged particles. However, it is challenging to reconstruct and analyze LArTPC events efficiently in large scale detectors. In this talk, I will review some revolutionary ideas in machine learning, and demonstrate the use of these techniques to tackle the challenge in LArTPC event reconstruction.

Daniel Ruterbories (Rochester U) "Electroweak Probes of the Nucleus and the Era of Precision Neutrino Physics"
2020-03-17 16:00 - 17:00 | Zoom Talk, 50A-5132, Berkeley, ca, 94720
ABSTRACT:
Neutrino oscillation experiments such as NOvA and T2K search for the disappearance and appearance of muon and electron flavor neutrinos in a predominately muon-type beam. These experiments are currently measuring the oscillation parameters to greater precision but will not be able to measure the CP phase with enough significance to pin down CP violation in the lepton sector. The next generation of experiments, DUNE and Hyper-Kamiokande, will push the field into its precision era, requiring precise predictions of the flux and neutrino interactions used to measure CP violation.
The MINERvA experiment is a dedicated neutrino interaction experiment set in the NuMI beamline at Fermi National Accelerator Laboratory. The purpose of the experiment is to measure neutrino interactions off a variety of nuclear targets to probe nuclear effects and inform modeling of neutrino interactions. The experiment measures interactions over a wide range of Q2 and W kinematics. These including interactions in the quasi-elastic, resonant, and shallow to deep inelastic scattering regions. The experiment has run with two beam energies peaked at ~3 and 6 GeV in both neutrino and anti-neutrino enhanced modes.
In this seminar, I will describe the current state of neutrino-nucleus interaction physics and how MINERvA data will inform future experiments. Specifically, I will describe the extensive tuning exercise MINERvA has done to describe interactions in the quasi-elastic into the resonant pion regions of kinematic phase space. I will also discuss lessons learned and describe some of the next generation measurements necessary to prepare for the DUNE experiment.

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Masha Baryakhtar (NYU) " New Physics Across the Spectra"
2020-03-19 16:00 - 17:00
ABSTRACT:
Theories beyond the Standard Model of particle physics often predict new, light, feebly interacting particles whose discovery requires novel search strategies. A light particle, the QCD axion, elegantly solves the outstanding strong-CP problem of the Standard Model; cousins of the QCD axion can also appear, and are natural dark matter candidates. First, I will discuss my experimental proposal based on thin films, in which dark matter can efficiently convert to detectable single photons. A prototype experiment is underway, and current techniques promise to reach significant new dark matter parameter space.
Second, I will show how rotating black holes turn into axionic beacons. When an axion’s Compton wavelength is comparable to a black hole size, energy and angular momentum from the black hole source exponentially-growing bound states of particles. I will discuss new results on axion interactions, including new dynamics in the bound states, and show how black holes populate the universe with axion waves that can be detected in future laboratory searches.

Christopher Marshall (LBNL) "The Dawn of DUNE: Neutrino Oscillations in the Precision Era"
2020-03-24 16:00 - 17:00 | 50-Auditorium
ABSTRACT:
Neutrino oscillation is a well-established phenomenon. Over the past two decades, nearly all of the parameters governing these oscillations have been measured experimentally, using neutrinos from the atmosphere, the sun, nuclear reactors, and particle accelerators. The remaining unknowns have very interesting consequences but are challenging to access experimentally as they require high-precision measurements. The Deep Underground Neutrino Experiment (DUNE) will be sensitive to these unknowns, including whether neutrinos violate CP symmetry, which could be the key to understanding why the universe is matter-dominated. Constraining systematic uncertainties is critical for DUNE to reach its physics goals, and requires a highly-capable near detector. I will present the discovery potential of DUNE and discuss how the experiment is designed to address the many challenges of precision neutrino oscillation physics. I will give particular focus to how the near detector can mitigate large uncertainties on the neutrino flux prediction and interaction cross sections.

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Richard Bonventre (LBNL) "Searching for Muon to Electron Conversion: The Mu2e Experiment at Fermilab"
2020-03-26 16:00 - 17:00 | 50-Auditorium

Adi Ashkenazi (Fermilab) "Probing V Interactions for V Physics"
2020-03-31 16:00 - 17:00 | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

The ability of current and next generation accelerator based neutrino oscillation measurements to reach their desired sensitivity requires a high-level of understanding of the neutrino-nucleus interactions. These include precise estimation of the relevant cross sections and the reconstruction of the incident neutrino energy from the measured final state particles. Incomplete understanding of these interactions can skew the reconstructed neutrino spectrum and thereby bias the extraction of fundamental oscillation parameters and searches for new physics. In this talk I will present the first exclusive differential cross section measurement using neutrino-Argon Quasi Elastic like interactions from the MicroBooNE experiment. In addition, using wide phase-space electron scattering data, collected using the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility (JLab), the reconstruction of the incoming lepton energy from the measured final state is being tested. Disagreements with current event generators, used in the analysis of neutrino oscillation measurements, are observed which indicate underestimation of nuclear effects. The impact of these findings on bias in oscillation analyses will be discussed.

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Lina Necib (Caltech) "Dark Matter in the Era of Gaia"
2020-04-02 16:00 - 17:00 | Zoom Talk, 50A-5132, Berkeley, ca, 94720
ABSTRACT:
The Gaia mission has provided distance and velocity measurements of over a billion stars in the Milky Way, making it the largest stellar catalog at hand. Simultaneously, recent developments in cosmological simulations have made it possible to track stars and dark matter in realistic Milky Way-like galaxies. In this talk, I will demonstrate how using cutting-edge simulations and Gaia data in tandem has enabled me to start building the first local map of the cold dark matter phase space distribution in our Galaxy. Doing so led me to discover Nyx, a stream of stars in the solar neighborhood that I identified using machine learning methods. Nyx, potentially the result of a prograde merger, is crucial in understanding the formation of the disk of the Milky Way as it might have been associated with an accreted dark disk. Finally, I will summarize how future surveys will help fully map out the phase space distribution of dark matter in the Milky Way, and show that such an empirical map will have extensive ramifications for dark matter searches.

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