INPA

Speaker: Jiamin Hou - Max-Planck - Institute for Extraterrestrial Physics
2020-01-24 12:00 - 13:00 (America/Los_Angeles)
Title: Clustering measurements in the final eBOSS quasar sample and their cosmological implications
Abstract:In this talk I present the clustering analysis of the final extended Baryon Oscillation Spectroscopic Survey (eBOSS) quasar sample at redshift 0.8<z<2.2, which bridges the redshift gap between the eBOSS LRG and Lyman-alpha measurements. Mapping the evolution of the expansion and growth of structure histories of our Universe provides us with a crucial test of the standard LCDM cosmological scenario. Our analysis includes a detailed modelling of the impact of the non-linear evolution of density fluctuations, bias, and redshift-space distortions on the two-point correlation function. Using numerical simulations designed to reproduce the uniqueness of the quasar sample, we perform extensive validation tests to characterise potential systematic errors induced by theoretical and observational effects. The constraints obtained from anisotropic clustering measurements can be used to test models of gravity on large-scales. However, these tests require the validation of our analysis techniques in modified gravity scenarios. I present an example of such tests, based on large numerical simulations of standard and modified gravity models to measure galaxy clustering in redshift space.

Speaker: Arnaud De Mattia - IRFU, CEA, Université Paris-Saclay
2020-01-17 12:00 - 13:00
Title: The extended Baryon Oscillation Spectroscopic Survey: clustering measurements, lessons, and prospects
Abstract: In this talk, I will present the clustering analysis of the ELG (Emission Line Galaxy) sample from the eBOSS (extended Baryon Oscillation Spectroscopic Survey) program of the Sloan Digital Sky Survey and review the other clustering analyses of the eBOSS program, dedicated to Luminous Red Galaxies and Quasars. I will discuss theoretical, observational and analysis systematics, how they were estimated and mitigated, focusing on the improvements over the last release of the BOSS program in 2016. Specifically, I will start by presenting the extensive work of the eBOSS collaboration to test model predictions against N-body simulations. The different observational systematics of the eBOSS samples will be reviewed, as well as the adopted correction schemes and the new analysis techniques used to mitigate residual systematics. Different analysis assumptions and their impact on the clustering signal will be discussed. After a review of eBOSS legacy cosmological measurements, I will finish by drawing lessons and prospects for future galaxy surveys.

Speaker: Samuel Hinton - University of Queensland
2020-01-10 12:00 - 13:00
Title: Challenges and pathways forward in supernova cosmology
Abstract: Using the DES photometric supernova cosmology analysis as groundwork, I will summarise our current analysis methodologies, from simulations, to transient classification, selection effect treatment, and cosmology. Despite recent improvements in analysis methods, there still exist fundamental challenges in areas spanning the initial empirical SN Ia model all the way to failing approximations built into cosmology fitters. I will highlight potential solutions to these challenges, to allow the next generation of surveys to lower the systematic floor and provide improved cosmological constraints. Additionally, I will also summarise my BAO and pipeline work for surveys like DESI, and discuss ways I’ve improved scientific workflow to allow more efficient use of researcher time.

Speaker: Suk Sien Tie - Ohio State University
2019-12-06 12:00 - 13:00
Title: Cosmology with the Lya forest: beyond two-point statistics, DESI instrumentation
Abstract: The Lyman-alpha forest is currently the only probe of cosmology and the state of the intergalactic medium (IGM) between redshifts of z=2 and 6. It’s higher-order clustering, specifically its three-point correlation function (3PCF), contains information that can help to constrain fluctuations in the ionizing background and temperature fields of the IGM, thus providing a novel way to constrain their effects on cosmological analyses of the LyA forest. In this talk, I will present theoretical predictions of the 3PCF of the LyA forest, considering both a uniform and spatially varying UV background. I will discuss the exciting possibilities that future surveys like DESI will enable in this area. Finally, I will present my instrumentation work on the DESI sky camera and the fiber positioner anti-collision algorithm, and how they facilitate the DESI survey to achieve its science goals.

Speaker: Chirag Modi - University of California, Berkeley
2019-11-22 12:00 - 13:00
Title: Reconstruction of Cosmological Fields in Forward Model Framework – Galaxy Clustering and Intensity Mapping
Abstract:
In this talk, I will outline the forward model approach to reconstruct cosmological fields in a Bayesian framework. I will focus on two examples – galaxy clustering and neutral hydrogen intensity mapping.
In galaxy clustering example, I will use the observations of galaxy surveys to reconstruct the initial Lagrangian field.
Here, we develop a novel framework with neural networks to forward model halo masses and positions and demonstrate that our method outperforms standard reconstruction in both real and redshift space.
This reconstructed initial field has enhanced signal for baryon acoustic oscillations and can enhance science returns for surveys like DESI.
For neutral hydrogen surveys, we lose over 50% of the modes at high redshifts due to foregrounds and it severely hampers their feasibility for cosmological analysis.
With a novel bias framework for the forward model, I will show that we are able to reconstruct over 90% of these modes and this recovers cross-correlations with photo-z surveys like LSST and tracers like CMB lensing. Lastly, I will briefly touch upon assumptions made in this reconstruction framework regarding noise models and likelihood. I will discuss preliminary ways to improve upon them using deep learning.

Speaker: Solène Chabanier - IRFU, CEA, Université Paris-Saclay
2019-11-08 12:00 - 13:00
The title and abstract are forthcoming.

Speaker: Katherine Rawlins - University of Alaska at Anchorage
2019-10-25 12:00 - 13:00

Speaker: Mattia Beretta - Development & Application of Scintillation Detectors for Rare Events Searches
2019-10-11 12:00 - 13:00

Speaker: Daniel Whiteson - What has the Machine Learned?
2019-10-04 12:00 - 13:00 | INPA Common Room, 50-5026

Will Thompson - COSINE-100 (Yale)
2019-07-12 12:00 - 13:00
TBA

Adam Bernstein (LLNL) - The Watchman Experiment
2019-06-28 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA

Vid Irsic (UW) - Lyman-alpha forest
2019-05-24 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA

Ben Land (UCB) - Solar neutrinos with SNO, SNO+, and Beyond
2019-05-17 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
This seminar gives a brief historical introduction to solar neutrino detection, and motivates the use of solar neutrinos as a tool to probe physics beyond the standard model. An analysis of SNO data constraining the lifetime of neutrino decay is presented, along with solar neutrino results from SNO+ water phase. Additionally, R&D for simultaneous detection of Cherenkov and scintillation light in future solar neutrino experiments is discussed, with a first look at single photon detection characteristics of LAPPDs.

NO INPA SEMINAR MTG
2019-05-10 12:00 - 13:00 | INPA Common Room, 50-5026

Maria Simanovskaia (UCB) - Searching for Dark Matter Axions with HAYSTAC
2019-05-03 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
Continuing on the topic of axion searches from last week, this seminar will highlight one experiment, HAYSTAC, which looks for an axion-induced power excess spectrally coincident with the resonance of a microwave cavity immersed in a strong magnetic field. This is the first such experiment to incorporate a dilution refrigerator and Josephson parametric amplifier and thereby achieve near-quantum-limited noise performance. Results will be discussed, as well as planned upgrades and research and development work for the future.

Karl van Bibber (UCB) - A Primer on the Axion
2019-04-26 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
This is the first of a two-part series on the axion and the current experimental campaign to find it. This first seminar will focus on the history and motivation of the axion, rooted in the Strong-CP problem, i.e. the absence of the neutron electric dipole moment, some phenomenology, and an overview of experimental avenues to detect the axion. In the second part next week, by Maria Simanovskaia, one particular experiment, HAYSTAC will be presented in detail, which searches for the axion as the dark matter of the universe.

NO INPA SEMINAR MTG
2019-04-19 12:00 - 13:00, 2019-03-15 12:00 - 13:00, 2019-03-08 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA

NO INPA SEMINAR MTG
2019-04-12 12:00 - 13:00

SPECIAL - Rajesh Sankaran - (ANL) - Waggle and Array of Things
2019-04-08 10:30 - 11:30 | 50-Auditorium
The Waggle Platform is a research project at Argonne National Laboratory to
design, develop, and deploy a novel wireless sensor platform with advanced edge
computing capabilities to enable a new breed of sensor-driven environmental
science and smart city research. The software and hardware designs from the
Waggle project are used by the NSF funded Array Of Things, which is building
a smart city and open data with urban sensors in Chicago. The innovative
architecture leverages emerging technology in low-power processors, sensors,
and cloud computing to build powerful and reliable sensor nodes that can
actively analyze and respond to data. Cloud computing provides elastic resources
for storing and computing on data. Waggle is designed from the ground up with
security, privacy, extensibility, and survivability as key design points. The
Waggle reference platforms and software are launching points. All of the
software is Open Source, and the software is modular, so researchers can add
their own sensors, computing pipelines, and data analysis. The talk will discuss
the various technical aspects of the Waggle platform and the Array of Things
urban deployment.

Giovanni Benato (UCB, LBL) - Waiting for neutrinoless double beta decay with cryogenic calorimeters
2019-04-05 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
Neutrinoless double beta decay is the matter-creating process that is most accessible with the current technology.
Its discovery would demonstrate the non-conservation of lepton number and that neutrinos have a Majorana mass component, and indicate a possible solution for the baryon asymmetry of the universe.
In this seminar, I will review the current status of the search for neutrinoless double beta decay,
discussing the recent developments of models for the calculation of nuclear matrix elements,
and the various possible mechanisms contributing to the process.
In addition, I will report on the current status of the CUORE experiment for the search of neutrinoless double beta decay with cryogenic calorimeters, and on the plans for its upgrade, CUPID.

Morgan Askins (UCB) - Search for invisible nucleon decay in the SNO+ detector
2019-03-29 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
Many Grand Unified Theories predict processes that would allow baryons to decay to leptons, violating baryon number conservation. The observation of baryon number violation in nucleon decay would be a revelation as well as being pivotal in understanding the apparent asymmetry between baryons and anti-baryons in the universe. This is manifest in some theories primarily through the decay of nucleons to three chargeless leptons (e.g. n to 3 neutrino), which can only be observed through the resulting nuclear deexcitation gamma. This “invisible” nucleon decay could be observable in water through the deexcitation of the resulting oxygen-15 nucleus which emits a 6.2 MeV gamma and requires that backgrounds at these energies, in a large detector, to be extremely low. Presented here are the first results from the SNO+ light water phase which consists of nearly 120 days of live data taking. A blind analysis was performed using a Poisson counting method and a maximum likelihood method independently to obtain the results.

Aaron Manalaysay (UC Davis) - 178 nm: The magic of liquid xenon and the search for dark matter
2019-03-22 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
The introduction of liquid-xenon (LXe) to the field of dark-matter direct detection caused a paradigm shift in this search. Primarily focused on the search for the Weakly Interacting Massive Particle, LXe detectors have improved our sensitivity to these dark-matter candidates by a factor of 10,000 since their introduction roughly ten years ago, compared to the factor of 50 sensitivity improvement that the field had covered in the twenty years before that. The rapid pace at which LXe detectors have pushed the field is due in part to their ability to scale to arbitrarily large size, thereby drastically reducing the rates of background signals in these rare-event searches. Though these detectors have seen tremendous successes, each result has been accompanied by its own set of challenges to be overcome, which will also be true for the next generation experiments. I will describe the most recent such U.S.-based experiment, LUX, and highlight the key innovative analyses that led to its impressive results. I will extend the discussion to cover LUX’s upcoming LBL-led successor, LZ, which will be sensitive to WIMP-nucleus interactions as rare as roughly 0.5 events/kg/millennium. Time permitting, I will expand the view by discussing the ways in which LXe is a powerful tool for probing non-WIMP dark-matter candidates.

Dr. Quentin Riffard (LBL) - Direct detection of Dark Matter: from LUX to LZ
2019-03-01 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
Liquid xenon two-phase time projection chamber (TPC) is one of the most promising technologies for WIMP dark matter direct detection. By using this technology, the LUX, XENON1T, and PANDAX-II collaborations established the most stringent limits on WIMP-nucleus cross section above 10 GeV. For WIMP searches, the expected signal is composed of nuclear recoils (NR), while our background is composed by both electron recoils (ER) and NR. The limits on the WIMP-nucleus cross section are extracted using a Profile Likelihood Ratio (PLR). The usage of the PLR requires a precise knowledge of signal and background models. In the first section, I will focus on the improvement of the detector response modeling and the re-analysis of the background model for LUX Run4 analyses. The LUX Run4 represents a challenge for the modeling of the detector response as several experimental parameters vary as a function of time. Then I will present a new detector response model based on the NEST yield model to consider those variations. This new model has been tuned on Run4 calibration data across many electric fields. After the decommissioning of the LUX experiment, some parts of the detector have been re-assayed to reevaluate the activity of the contaminants. I’m developing a new background model based on a Monte-Carlo simulation of the detector and those new measurements. Once achieved, this background model will be used in future analyses. I used the new detector response model to test the impact of the electric field and the light collection efficiency on detector sensitivity for several dark matter models.
Among few collaborations, the LUX-ZEPLIN (LZ) is currently building one of the next generation of dark matter detector. The NR response detector calibration is a fundamental aspect of dark matter searches. I am involved in development of a photo-neutron source for the low energy NR calibration of the detector. By using a Monte-Carlo simulation, we determined the expected event rate. Moreover, by using photo neutron simulations, I also identify a plausible low energy calibration source. After Xe neutron capture, we have the emission of very high energy gammas ~ 9 MeV and a ~300 eV NR. In some case only the NR is visible as the gamma can escape the LXe without depositing any energy. By using the veto to tag this neutron capture reaction, I show that we have a new possible low energy NR internal calibration source.

Jia Liu (Princeton) - Nonlinear cosmology with massive neutrinos
2019-02-22 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
The non-zero mass of neutrinos suppresses the growth of cosmic structure on small scales. Since the level of suppression depends on the masses of the three active neutrino species, the evolution of large-scale structure is a promising tool to constrain the total mass of neutrinos and possibly shed light on the mass hierarchy. I will discuss recent progress and future prospects to constrain the neutrino mass sum with cosmology, with a focus on the nonlinear regime.

Alexander Fieguth (Stanford) - Recent results of the Xenon-1t dark matter experiment
2019-02-15 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
Beyond the Standard Model of particle physics there exists a form of matter, which seems to be dark in all interaction channels but in its gravitational influence. The nature of this major constituent of the universe is still not understood. The assumption that it is made up of particles which can possibly leave a trace in any detection channel is an established concept since decades.
Weakly Interacting Massive Particles (WIMPs) are one of the promising candidates for dark matter constituents. The hunt for a direct detection of a WIMP scattering off a target nucleus on earth is ongoing and pursued with larger efforts than ever before. Among different experiments, the dual-phase xenon time projection chambers are the most sensitive detectors for scatterings between WIMPs above a few GeV/c^2 and normal matter. The XENON1T experiment located at LNGS is such a detector. Using an exposure of one (tonne x yr) a null-result was obtained and this way the parameter space was probed down to a minimum of 4.1 x 10^(-47) cm^2 for a 30 GeV/c^2 WIMP at 90% C.L. A crucial aspect behind its sensitivity is the mitigation and understanding of background sources mimicking a WIMP signal. Notably, the rate of electronic recoils in the detector (82^(+5)_(−3) (sys.) ± 3 (stat)) events/(tonne×yr×keV) is the lowest achieved in any dark matter detector.
An introduction to the general direct detection principle will be given in this talk. Furthermore, the experimental picture of direct dark matter search will be introduced with a focus on the results from the XENON1T experiment. In addition, an outlook on recent efforts to open up for scenarios beyond the vanilla dark matter search, e.g. the interaction of WIMPS purely with pions within the nucleus, will be included. Finally, an insight into the possibilities a large liquid xenon low background detector offers for physics channels beyond the dark matter search will be given.

Sinead Griffin (LBL) - Materials considerations for New Dark Matter Detectors
2019-02-08 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
New discoveries in quantum information science and in dark matter detection rely on finding more sensitive detectors than those in state-of-the-art experiments. Traditional detector technologies, based on nuclear and electron scattering, have a lower bound on their sensitivity depending on the target’s mass and bandgap. We investigate two classes of new low-threshold detector target materials — Dirac electrons and optical phonons — using first-principles calculations. We discuss how the dark matter/target interaction can be optimized using chemical and physical engineering, and present the target reach for these new dark matter detection proposals.

Hillary Child - Nonlinear Structure Formation at Two Scales: from Bispectrum Baryon Acoustic Oscillations to Evolution of Halo Profiles
2019-02-01 12:00 - 13:00 | 50A-5132- Sessler, 50A-5132 Sessler Conference Room, CA
The “cosmic web” of dark matter halos forms via the collapse of post-inflation density fluctuations. While linear perturbation theory describes this process well at large scales and low densities, it fails at small scales and high densities. I explore two facets of nonlinear structure formation that constrain cosmology: at mildly nonlinear scales, measuring the baryon acoustic oscillation (BAO) distance scale in the bispectrum, and at deeply nonlinear scales, tracking the evolution of simulated dark matter halo profiles.

At mildly nonlinear scales, the BAO distance scale constrains the expansion history of the universe and dark energy. The BAO feature has been detected in both the three-point correlation function and the bispectrum, but challenges remain in fully exploiting three-point data. I present a strategy to select triangle configurations that maximize the amplitude of the BAO signal in the bispectrum. A relatively small set of bispectrum measurements can improve constraints on the BAO length scale over power spectrum measurements alone.

I next turn to the internal structure of dark matter halos, whose formation is highly nonlinear. The spherically-averaged density of a halo is well described by the Navarro-Frenk-White (NFW) profile, a function of two parameters: concentration, which describes the density of the central region of the halo, and halo mass. These two parameters are correlated, and the resulting concentration-mass (c-M) relation is sensitive to cosmological parameters. I present a robust measurement of the c-M relation from the largest ever sample of simulated halos (~30 million) and track the evolution of individual halos to connect halo formation time and concentration.

SPECIAL - Brittany Kamai (CalTech) - Looking further back with LIGO
2019-01-30 12:00 - 13:00 | INPA Common Room, 50-5026
Gravitational wave detectors require constant innovation in detector technology to meet the growing needs of the astrophysics community. With improved sensitivity, we can move beyond the measurements in the local universe and perform precision tests of cosmology. I will discuss our efforts to reduce the amount of low frequency noise within the LIGO detectors, which has a direct impact on our ability to measure heavier mass black hole mergers further out into the universe. I will focus on a proposed major upgrade to the LIGO detectors that will use silicon optics cooled to cryogenic temperatures. Additionally, I will discuss ideas for a passive seismic isolation system that uses advances in seismic cloaking technology. These improvements will extend distance measurements on gravitational wave mergers from the local universe out to much higher redshifts.
