LBNL Physics Division Research Progress Meetings

Mengjiao Xiao (University of Maryland) "Probing the Nature of the Universe from the Chinese Underground Experiments"
2018-01-11 16:00 - 17:00 (America/Los_Angeles) | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Despite the tremendous success of the Standard Model (SM) of particle physics, it becomes more and more clear that the SM is far from complete. For example, the non-zero neutrino mass was the first solid evidence beyond the SM, but we still do not understand why neutrinos are so light, and if they are their own anti-particles. We know that the mass of the universe is dominated by dark matter, but we do not understand the nature of the dark matter. Exploring these unknowns may lead to fundamental science discoveries and deepen our understanding of the universe.
Due to their feeble interactions with normal matter, both neutrinos and dark matter are studied under low background environment in underground laboratories. This area of research is booming in China with a few underground facilities in operation or under construction. The first half of my talk will introduce the Jiangmen Underground Neutrino Observatory (JUNO), an experiment aiming to determine the neutrino mass ordering and to precisely measure oscillation parameters using a large liquid scintillator detector. I will then discuss the PandaX project, a series of experiments using dual-phase xenon for dark matter direct detection in the China Jin-Ping underground Laboratory.
Bio:
Mengjiao Xiao, Ph.D. of Shanghai Jiao Tong University in 2016, now is postdoc at University of Maryland, College Park. Working on PandaX and JUNO experiment.

Oindree Banerjee (Ohio State University) "Searching for ultra-high-energy neutrinos with the Antarctic Impulsive Transient Antenna "
2018-01-09 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

Ultra-high-energy (> 10^18 eV) neutrinos remain undiscovered in this era of rapid growth in multi-messenger astronomy. These neutral and weakly-interacting particles can travel cosmic distances without attenuation and point straight back to their source, rendering them promising messengers. Detection of these elusive particles requires an enormous instrumented volume of a dielectric material such as water, ice, salt, etc. Use of radio Cherenkov method enables this at a relatively low cost. The Antarctic Impulsive Transient Antenna (ANITA) is a NASA-funded long-duration balloon experiment that is launched from near McMurdo Station, Antarctica, to fly over the continent in roughly circular orbits in the stratosphere for a month. ANITA looks for the radio signature from ultra-high-energy neutrino interaction in the ice below. There have been four flights of ANITA so far. I will review the principles underlying radio detection of neutrinos by ANITA, the ANITA instrument and recent developments in the hardware and electronics of ANITA. I will show results from the currently ongoing search for a diffuse flux of neutrinos in the data from the third flight of ANITA.

Bio:

I received my Bachelor’s degree in Physics from North Carolina State University. Currently, I am a 5th year graduate student in Physics at Ohio State University. For the ANITA-IV mission, I built, tested and deployed electronics which, for the first time, were able to dynamically filter anthropogenic noise at tunable frequencies. These filters helped to triple the “effective livetime” of ANITA-IV compared to ANITA-III. In analysis, I am working on new techniques for background rejection using data from the ANITA-II and ANITA-III flights.

Luise Poley (Humboldt U.) "Testbeam studies for the ATLAS ITk strip tracker"
2017-12-19 11:00 - 12:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract
During Long Shutdown 3 (2024/2025) of the Large Hadron Collider, the ATLAS Inner Detector will be replaced with a new all-silicon tracker, composed of a pixel and a strip tracker. The strip tracker will consist of 18,000 detector modules, each comprised of a silicon strip sensor with readout electronics glued on to its surface.
Extensive quality assurance and quality control programmes have been established for module components as well as combined structures in order to ensure high reliability and efficiency. Among different methods to test components and modules, measurements in particle beams (testbeams) provide operating conditions similar to the LHC and thus are critical for understanding the detector performance.
This talk presents measurements performed using an electron beam at the DESY-II testbeam facility and X-ray photons at the Diamond Light Source. The results show the influence of different sensor architectures on the module performance, how testbeams can improve the understanding of material distribution in the detector and how these measurements can benefit the future ATLAS detector.
BIO:
I have studied at the Humboldt-Universität zu Berlin, where I worked on ATLAS analysis (b-tagging efficiencies) for my bachelor thesis. I joined the ITk strip tracker project in 2012, when I started to work at DESY for my master thesis and later for my PhD. Since 2015, I have participated in all ITk testbeam activities at DESY and organised nine testbeams myself.

Michaela Queitsch-Maitland (DESY) Title: "Precision measurements of Higgs boson production and the search for dark matter in ttbar events at the LHC"
2017-12-12 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
“Despite the huge success of the Standard Model (SM), there is overwhelming evidence for physics beyond the SM and many remaining questions, such as the nature of dark matter (DM). The current leading candidate for DM are Weakly Interacting Massive Particles (WIMPs), which could be produced directly at colliders.
In this talk I will discuss complimentary methods for exploring new phenomena at the LHC with the ATLAS experiment. Firstly, through precision measurements of the Higgs boson properties, and secondly though the production of missing transverse energy in association with pairs of top quarks.
Finally, I will discuss the High Luminosity LHC (HL-LHC) project and the ATLAS inner tracker (ITk) upgrade, focusing on characterising the end-of-lifetime performance and validations of material budget estimates.”

Daniel Baxter (Northwestern University) Probing the Dark Sector: The Quest for a Background-Free Detector
2017-12-07 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Dark matter represents one of the most sought after discoveries in physics. Leading theories predict that extremely sensitive detectors could probe nuclear recoils from dark matter interactions. The PICO collaboration uses bubble chambers to look for the energy deposition from such an interaction. The biggest challenge in searching for dark matter is the mitigation and understanding of the numerous other sources of events that could look like dark matter, namely radioactive backgrounds. I will discuss how a long effort to understand backgrounds in the PICO bubble chambers led to the recent background-free result of PICO-60 and how discoveries made along the way might affect other rare event searches.
Bio:
Daniel Baxter is a graduating 5th year PhD student at Northwestern University and active member of the international PICO collaboration searching for dark matter using bubble chamber detectors. His research has largely focused on dark matter detector calibration, specifically understanding differences in detector response between nuclear and electron recoils. He has applied this expertise to the PICO-60 detector as run coordinator of its first physics run, which became the first background-free run of a bubble chamber at the 40L scale.

Syed haider Abidi (University of Toronto) "Measurement of Higgs Boson Properties & ITk Detector Development"
2017-11-30 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
During Run 1 of LHC, the ATLAS and CMS collaboration firmly established the existence of a Higgs boson but detailed measurements were limited by statistical precision. With the larger Run 2 dataset, we have measured the couplings and production cross-section of the Higgs boson using the H->ZZ->4l decay channel. The results improve upon the previous ones by more than a factor of 2. For the first time, we also measure the differential cross-section within production modes and use it to place constraints on Beyond Standard Model scenarios.
ATLAS has an extensive detector upgrade plan to allow itself to collect and exploit the data delivered during HL-LHC. The upgrade of the current inner track with the all- silicon ITk is the largest project. At University of Toronto, we have lead the Canadian effort to establish ITk strip module assembly. Collaborating with Celestica, we have also established ASIC gluing and wire-bonding processes in industry. Additionally, we are probing the impact of radiation damage to estimate the end-of-life performance of the ITk.
Bio:
As I have done my undergraduate training in Engineering Science, I have been interested in bringing this prospective to physics research. As such I have been involved in many research projects, ranging from condensed matter to accelerator development.
Since 2013, I have focused on measurements of Higgs boson properties using the ATLAS detector and ITk detector development. I have lead and been involved in numerous analyses using the H->ZZ->4l channel and analyses combining results from various other decay channels. Additionally I have led the development and investigation of ITk modules at University of Toronto. In the future, I intend to continue pursuing both physics analyses and detector hardware.

Patrick Bryant (U. Chicago) "Measuring Higgs Pair Production at the LHC - Why and How?
2017-11-21 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
As the universe cooled immediately following the Big Bang, the laws of physics underwent a dramatic phase transition. Underlying symmetries were broken and particles acquired mass as the Higgs field moved to a new ground state.
In this talk I will discuss why we should care about the precise nature of the electroweak phase transition (EWPT) and how the potential which generated the EWPT may be measured at the LHC.
Bio: Patrick received his B.S. in physics and mathematics at the University of Oregon in 2013 and has since been working towards his Ph.D. in experimental particle physics at the University of Chicago as a member of the ATLAS collaboration. He recently returned to Chicago after a year and a half at CERN in Geneva, Switzerland to write his thesis on hardware based track reconstruction and the search for Higgs pair production in the four b-jet final state.

Ulascan Sarica (John Hopkins U.) "Measurements of Mass, Width, Lifetime, and Anomalous Couplings of the H(125) Boson"
2017-11-16 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 completed the set of particles predicted by the Standard Model (SM). It has been established by the CMS and ATLAS Collaborations at the Large Hadron Collider that the discovered boson is consistent with J^PC=0^++. The width of this boson is also consistent with the predicted value from the SM, but the constraints using events at the resonance peak are orders of magnitude looser than the prediction. In this talk, we will be exploring techniques developed to probe small anomalous couplings of the Higgs boson. Emphasis will be given to the recent studies of Higgs-diboson (HVV) couplings from the CMS Collaboration, where information from associated production becomes even more important than the kinematics of Higgs decay products. We will also look at joint mass-width measurements using either events at the resonance peak or at the offshell tail of Higgs boson production. We will see that even small anomalous couplings show enhancement at the offshell tail and discuss briefly how joint constraints can be studied.

Bin Yu (University of California, Berkeley) "Three Principles of Data Science: Predictability, Stability, and Computability"
2017-11-09 16:00 - 17:00 | ca
ABSTRACT:
In this talk, I’d like to discuss the intertwining importance and connections of three principles of data science in the title in data-driven decisions.
Making prediction as its central task and embracing computation as its core, machine learning has enabled wide-ranging data-driven successes. Prediction is a useful way to check with reality. Good prediction implicitly assumes stability between past and future. Stability (relative to data and model perturbations) is also a minimum requirement for interpretability and reproducibility of data driven results (cf. Yu, 2013). It is closely related to uncertainty assessment. Obviously, both prediction and stability principles can not be employed without feasible computational algorithms, hence the importance of computability.
The three principles will be demonstrated in the context of two neuroscience projects and through analytical connections. In particular, the first project adds stability to predictive modeling used for reconstruction of movies from fMRI brain signlas to gain interpretability of the predictive model. The second project uses predictive transfer learning that combines
AlexNet, GoogleNet and VGG with single V4 neuron data for state-of-the-art prediction performance. It provides stable function characterization of neurons via (manifold) deep dream images from the predictive models in the difficult primate visual cortex V4. Our V4 results lend support, to a certain extent, to the resemblance of these CNNs to a primate brain.

Reserved
2017-11-07 16:00 - 17:00, 2017-11-02 16:00 - 17:00, 2017-10-31 08:00 - 17:00, 2017-10-26 08:00 - 17:00, 2017-10-24 08:00 - 17:00, 2017-10-17 08:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132

Anthony Pullen (NYU) Title: Revealing CII Emission with LSS Cross-correlations
2017-10-19 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

In this talk, I will present our joint measurement of cosmic infrared background (CIB) and CII line emission from large scales at redshift z=2.5 using an MCMC analysis of cross-correlations of the 3 high-frequency Planck bands with both SDSS-III quasars at z=2-3.2 and SDSS-III CMASS galaxies at z=0.43-0.7. The CII emission is expected to correlate with the quasars and appear in the Planck 545 GHz band, while the other cross-correlations are assumed to mostly be attributable to CIB-LSS correlations. We report an excess emission inconsistent with the null result at 95% confidence, with an intensity value favoring the higher range of CII models. I will also forecast potential CII intensity constraints from Planck cross-correlated with DESI quasars.

Barnabas Poczos (CMU) Title: Distribution Regression and its Applications
2017-10-12 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The most common machine learning algorithms operate on
finite-dimensional vectorial feature representations. In
many applications, however, the natural representation of the data
consists of more complex objects,
for example functions, distributions, and sets, rather than
ﬁnite-dimensional vectors. In this talk
we will discuss machine learning algorithms that can operate directly
on these complex
objects. For this purpose, we use nonparametric statistical methods
that can consistently estimate the inner product, distance, and
certain kernel functions between distributions, sets, and other
objects. We will discuss applications in various scientific areas
including cosmology (e.g. estimating the mass of galaxy clusters,
finding anomalous galaxy clusters, estimating the cosmological
parameters of our Universe, accelerating cosmological simulations),
fluid dynamics (finding anomalous events in turbulence data),
neuroimaging, and agriculture

Simeon Bird (JHU) "Strong Absorbers in the Lyman-alpha Forest and Primordial Black Holes"
2017-10-05 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Strong HI absorbers are essentially the largest foreground contamination for Lyman alpha forest surveys, and so a better understanding of them is necessary for achieving the goals of future Lyman alpha cosmology surveys. I will talk about a new automated technique for generating a probabilistic catalogue of strong absorbers for the entire survey, allowing more robust cleaning of the foreground. Since no technique can entirely remove strong absorbers, I will discuss new templates for characterising their effect on the flux power spectrum. A secondary systematic is induced by interpolation error between theoretical models, and I will discuss techniques to mitigate this error with refining Gaussian Process emulators. Lastly I will discuss the interesting possibility that the surprisingly common mergers of ~30 solar mass black holes observed by LIGO could be primordial black hole dark matter, which is intriguingly (still) not convincingly ruled out.

Bertrand Echenard (Caltech) "Probing light dark matter with the LDMX experiment"
2017-09-28 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
Elucidating the nature of dark matter is one of the central challenges
in fundamental physics. Dark matter originating as a thermal relic
from the early Universe is arguably one of the most compelling
paradigm, and WIMP searches have been the main focus of past
experimental efforts. Not as extensively explored, the possibility of
light (sub-GeV) thermal dark matter could arise naturally if it is
part of a dark sector neutral under all Standard Model forces. The
“Light Dark Matter eXperiment” (LDMX) proposes to explore light
thermal dark matter using an electron fixed-target missing momentum
approach with a low current, high-repetition beam. The expected
sensitivity would surpassing by orders of magnitude the reach of any
previous or currently envisioned experiment, and decisively test many
sub-GeV thermal dark matter scenarios.

Kev Abazajian (UC, Irvine) "Candidate Signals and Stringent Constraints from Dark Matter in the Sky"
2017-09-21 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
I will discuss analyses leading to two recent candidate detections of photons from dark matter. Specifically, these are: first, gamma rays in a continuum “bump” at a few GeV which can be due to WIMP-like dark matter annihilation in the Galactic Center; and, second, X-rays from clusters of galaxies and Andromeda consistent with monoenergetic 3.55 keV photons from dark matter decay such as that predicted from sterile neutrino dark matter. Commensurately, there are also stringent constraints on these signals. I will discuss the particle and cosmological model implications of both.

Cora Dvorkin (Harvard) "Discovering New Physics Beyond the Standard Model with Cosmological Data Sets"
2017-09-14 16:00 - 17:00 | 70A-3377, 70A-3377
Abstract:
Cosmological observations have provided us with answers to age-old questions, involving the age, geometry, and composition of the universe. However, there are profound questions that still remain unanswered. I will describe ongoing efforts to shed light on some of these questions.
In the first part of this talk, I will explain how we can use measurements of the CMB and the large-scale structure of the universe to reconstruct the detailed physics of much earlier epochs, when the universe was only a tiny fraction of a second old. In particular, I will show how we can probe the shape of the inflationary potential, extra degrees of freedom during inflation, and the signature of possible particles with mass and spin during this period.
In the last part of the talk, I will discuss how we can use observations at large scales and sub-galactic scales (through strong gravitational lensing) to improve our understanding of another open question in fundamental physics: the particle nature of dark matter.

Ben Nachman (LBNL) and Mateus Ploskon (LBNL) "Jet Substructure"
2017-08-31 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
The LBNL xTalk (“cross-talk”) series provides a forum for the exchange of ideas between groups and across lab divisions. Each seminar is focused on a theme which is confronted from two perspectives. In particular, the talks are given by two presenters from different domains. The format is informal (chalk talk!) and is designed to be entertaining and engaging. Come prepared to learn and ask about details with the experts in order to stimulate collaborations between groups. We hope that this will strengthen the program at the lab and spread new ideas.
For the first xTalk, we will have Mateusz Ploskon from Nuclear Science and Benjamin Nachman from the Physics Division to discuss how jet substructure is used in ALICE/STAR and in ATLAS. Jets are collimated sprays of particles resulting from quarks and gluons produced at high energy. The radiation pattern within jets encodes a wealth of information about the parton that initiated it. Jet substructure is a hot topic in pp for tagging boosted W/Z/H bosons and also recently for precision probes of Quantum Chromodynamics (QCD); in heavy ion collisions, jet substructure is an exciting new probe of medium modifications. Please join us for this comparative discussion of how jet substructure is used in two very different environments!

Larry Lee (Harvard) "Searches for Sneaky SUSY at the ATLAS Experiment"
2017-08-17 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
Despite the lack of a sparticle discovery at the Large Hadron Collider, and despite the fact that most of the discovery potential has shriveled to an upsetting size, supersymmetry (SUSY) remains the most motivated solution to the Standard Model’s inadequacies. Because of this (and a large dose of stubbornness), we are forced to consider ways the nominal search strategy may have missed a discovery. Must SUSY present itself with lots of high-momentum objects and large missing transverse energy just because it’d be easy to find? This talk will discuss recent SUSY searches at ATLAS targeting signatures without large missing transverse energy as well as those sensitive to long-lived sparticles.

Tova Holmes (ATLAS) "The FTK: Global Tracking for the ATLAS Trigger"
2017-08-15 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The ATLAS Detector is in the process of upgrading its Trigger and Data Acquisition system to include global processing of tracks using the FastTracKer (FTK). The FTK uses a parallelized structure to identify and reconstruct the properties of tracks from the 98 million channels of the the ATLAS silicon detectors. With the use of hardware-level pattern matching and a two-tiered track-fitting system, this reconstruction can be performed on all events passing the first-stage ATLAS trigger, with a rate up to 100 kHz and requiring less than 100 µs per event. These capability opens new doors for b-jet and tau triggering, allows for the suppression of pile-up effects on missing energy triggers, and can even be used to isolate BSM signatures involving long-lived particles. This talk will discuss the physics case for the FTK, an overview of its design, and its integration status.

Zachary Marshall (LBNL) "Title: Searching for SUSY in Big Data at the LHC"
2017-07-13 08:00 - 16:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
One of the most enticing and popular additions to the Standard Model of particle physics, Supersymmetry, is the target of a wide range of searches at the Large Hadron Collider at CERN. The ATLAS and CMS experiments have produced an incredible variety of searches, but Supersymmetry remains elusive. We will discuss the results of some of the recent searches that demonstrate the dexterity of both experiments, and point out which assumptions might be playing an important role in the interpretation of those results. There are still many ways Supersymmetry could have escaped detection up to now, and we will also point towards some of the next directions for searches for Supersymmetry at the LHC. Along the way, we will discuss some of the software and computing challenges that come with world-wide analysis of tens of billions of events, and how the

Marcel Vos (CERN) "Prospects for Top Physics at the LHC and Beyond"
2017-06-22 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
Experiments at the Large Hadron Collider are characterizing the top quark and its interactions to unexpected precision. The combination of direct searches for new particles and indirect constraints from precision measurements provides powerful limits on extensions of the Standard Model. I start the seminar with a brief overview of top physics today and of the prospects for precision top physics of future LHC runs. This sets a high bar for future colliders that are to continue the programme initiated by Tevatron and LHC. In the second half of the seminar I discuss the potential of the future facilities envisaged in Asia and Europe. Powerful electron-positron machines have exquisite potential for key measurements such as the top quark mass and electro-weak couplings. Hadron colliders with a center-of-mass energy that significantly exceeds that of the LHC can probe the QCD interactions of the top quark an order of magnitude deeper and can provide a precise measurement of the top Yukawa coupling.

Florian Beutler (Portsmouth) "On the reliability of Baryon Acoustic Oscillation (BAO) measurements"
2017-06-01 08:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

In this talk I will discuss the reliability of the Baryon Acoustic Oscillation (BAO) signal in the distribution of galaxies. The solid theoretical understanding of this observable means that it represents one of only a few cosmological observables that are not yet dominated by systematic errors. This is one reason why BAO are one of the main science drivers for future galaxy surveys like DESI and Euclid.

I will discuss my recent work on the relative velocity effect as one potential systematic for BAO. The relative velocity effect originates from the same physical effects which imprinted the BAO signal and therefore acts on the same scale. I will introduce this effect in detail, discuss how we can include it in our modeling and present current constraints from the Baryon Oscillation Spectroscopic Survey (BOSS).

Physical Sciences Institution Review
2017-05-23 08:00 - 2017-05-25 17:00 | ca

Prof. Rouven Essig (TBA) " Direct Detection of sub-GeV Dark Matter"
2017-05-11 16:00 - 17:00 | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
Dark matter makes up 85% of the matter in our Universe, but we have yet to learn its identity. A broad array of search strategies are needed to probe for non-gravitational interactions between dark matter and ordinary matter. While most searches focus on Weakly Interacting Massive Particles (WIMPs) with masses between 1 GeV and 1 TeV, it is imperative to also consider other motivated dark matter candidates. In this talk, I will discuss dark matter with MeV-to-GeV masses, which is a theoretically and phenomenologically appealing possibility and presents a new frontier in the search for dark matter. I will highlight novel dark matter direct-detection strategies that can probe this under-explored mass range. I will review how XENON10 data already probes dark matter with masses as low as a few MeV, and present recent constraints using XENON100 data. I will then discuss improvements expected from near-future experiments, focusing on xenon, semiconductor, and scintillator targets. This includes, for example, SENSEI, which is a new ultra-low-threshold silicon CCD detector that is poised to probe vast new regions of parameter space in the next few years. I will also present a few simple benchmark models of MeV-to-GeV dark matter, and contrast direct-detection probes with searches at colliders and fixed-target experiments.

Manoj Kaplighat (UC, Irvine) "The self-interacting dark matter paradigm: motivations and tests"
2017-05-04 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

I will describe how a simple model where dark matter has large elastic self-interactions (cross section over mass of order barns per GeV) can fully explain the observed diversity of all galactic rotation curves. I will summarize the constraints imposed on model building by observations of clusters of galaxies and end with an outline of tests of this paradigm.
