LBNL Physics Division Research Progress Meetings

Qian Xin (BNL) "Development of LArTPC for Neutrino Physics"
2018-10-11 16:00 - 17:00 (America/Los_Angeles) | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Liquid Argon Time Projection Chamber (LArTPC), with its mm-scale position resolution and the full-active-volume imaging-aided calorimetry, is an excellent device to detect accelerator neutrinos at GeV energy range. This technology may hold the key to search for new CP violation in the lepton sector, to determine the neutrino mass hierarchy, to precisely measure neutrino mixing parameters, to search for baryon number violation, and to search for sterile neutrino(s). In this talk, I will review the current status of the detector development. In particular, the challenges in TPC signal processing and event reconstruction will be discussed among other subjects.

Kyle Helson (NASA Goddard) "The Status and Outlook of Cosmic Microwave Background Polarization Measurements"
2018-10-04 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The detailed characterization of the intensity and polarization Cosmic Microwave Background (CMB) radiation provides a powerful tool to constrain the properties of early Universe. The polarization induced by a stochastic gravitational wave background in this epoch induces a distinctive and measurable signature of primordial inflationary processes. Presently the field has a healthy contingent of ground, balloon, and space based missions. In this talk I will discuss a brief history of CMB measurements, the current status of the field and outlook for the future. I will also discuss on-going work at NASA Goddard Space Flight Center on the development of polarization-sensitive detectors for a future satellite CMB polarization mission and their application in ground based instruments.

Matt Pyle (UCB) "Athermal Phonon Detectors: World Leading Light Mass Dark Matter Sensitivity From Athermal Phonon Detectors + Preliminary Performance from Large Area Photon Detector for Next Generation Neutrinoless Double Beta Decay Experiments"
2018-09-27 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:

In this talk, we present the new world leading results from the first search of the SuperCDMS collaboration for inelastic electronic recoils from low mass dark matter dark matter (500keV – 100MeV) using our new single ionization sensitive cryogenic calorimeters.

We’ll also present preliminary performance of a large area cryogenic photon detector with applications in light mass dark matter and neutrinoless double beta decay. With 3eV sensitivity and 20us pulse rise time, it well surpasses all technical requirements for next generation cryogenic neutrinoless double beta decay experiments.

Martin White (UCB) "The cosmological legacy of Planck "
2018-09-20 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
The anisotropies in the cosmic microwave background radiation have become our most important cosmological fossil. The study of these “echoes of gravity” has revolutionized cosmology, stringently tested our models and allowed precise measurement of a host of important cosmological parameters. I will discuss how far we’ve come since the early detections of CMB anisotropies and in particular the cosmological legacy of the Planck mission.

Sinead Farrington (U. Warwick) "Physics with Taus"
2018-09-06 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The identification of hadronically decaying tau leptons at the LHC is challenging. I will review the methods for tau reconstruction at ATLAS and how the identification of tau leptons has enabled several interesting and novel measurements in exotics and Higgs physics at the LHC. I will also look to the future and give some thoughts on next implementations for tau leptons at the LHC.

Laura Newburgh (Yale U.) "New Probes of Old Structure: Cosmology with 21cm Intensity Mapping and the Cosmic Microwave Background"
2018-07-19 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
Current cosmological measurements have left us with deep questions about our Universe: What caused the expansion of the Universe at the earliest times? How did structure form? What is Dark Energy and does it evolve with time? New experiments like CHIME, HIRAX, and ACTPol are poised to address these questions through 3-dimensional maps of structure and measurements of the polarized Cosmic Microwave Background. In this talk, I will describe how we will use 21cm intensity measurements from CHIME and HIRAX to place sensitive constraints on Dark Energy between redshifts 0.8 — 2.5, a poorly probed era corresponding to when Dark Energy began to impact the expansion history of the Universe. I will also discuss how we will use data from new instruments on the ACT telescope to constrain cosmological parameters like the total neutrino mass and probe structure at late times.
Slides Here

Yuri Gershtein (Rutgers U.) "CMS Tracker for HL-LHC: an Exciting New Tool for Discovery"
2018-07-10 16:00 - 17:00
Abstract
The radiation environment at the High Luminosity LHC requires CMS to
replace its silicon tracker with one that is more radiation hard and granular.
The new tracker is designed twenty years after the original one, and has new unique
capabilities. It spans 8 units in rapidity, is more then twice lighter, and is capable to
participate in the first level of trigger decisions. In this talk, after sketching the
HL-LHC physics case, I will describe the detector design, FPGA-based track reconstruction,
and focus on one of many possible new opportunities it provides for new physics searches.

Adam Becker (UCB) "An Incomplete Survey of Proposed Solutions to the Quantum Measurement Problem"
2018-06-28 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
The central puzzle that drives the field of quantum foundations is the measurement problem: what gives rise to the appearance of wave function collapse? While there is no single answer to this question that has wide acceptance, this is not for lack of available options. A variety of solutions to the measurement problem have been proposed, in the form of various interpretations or modifications of quantum mechanics. Some solutions eliminate collapse entirely, as in the many-worlds and de Broglie-Bohm interpretations. Others propose altering the dynamics of the theory to make collapse objective, as in GRW (stochastic collapse) and gravitational collapse theories. “Psi-epistemic” interpretations attempt to dissolve the measurement problem by claiming that the wave function isn’t something real in itself, but merely a representation of our knowledge of an underlying reality. Finally, Copenhagen-style interpretations claim that that there is no “reality” to be talked about at all. Bounding this menagerie of interpretations are several important theorems that restrict the options available. Bell’s theorem is the most famous (and most misunderstood) of these, but it is not the only one. In this talk, I will briefly lay out the measurement problem and its history, go over several of the theorems that constrain the possible solutions, and discuss a few of the families of quantum interpretations and the open problems that remain for each of them.
Slides here

Joshua Spitz (U. Michigan) " First Measurement of Monoenergetic Muon Neutrino Charged Current Interactions
2018-06-21 08:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
This talk will present the first measurement of monoenergetic muon
neutrino charged current interactions. The MiniBooNE experiment at
Fermilab has been used to isolate and study 236 MeV muon neutrino
events originating from charged kaon decay at rest. The muon
kinematics and total cross section have been extracted from this data.
Notably, this result is the first known-energy, weak-interaction-only
probe of the nucleus to yield a measurement of omega (energy
transferred to the nucleus) using neutrinos, a quantity thus far only
accessible through electron scattering. I will discuss the
significance of this measurement, and these monoenergetic neutrinos in
general, for elucidating both the neutrino-nucleus interaction and
oscillations.
Slides here

Norbert Zacharias (USNO) "Impact of Gaia on Astrometry and Beyond"
2018-06-14 16:00 - 17:00 | INPA Common Room (50-5026), 50-5026
April 2018 marks the 2nd data release (DR2) of the ESA Gaia space mission.
A new era in astrometry begun. Accurate positions, proper motions
and parallaxes for over a billion stars are now available on the
sub-mas level. The properties of DR2 will be explained in context
to pre-Gaia data and the final Gaia results expected in a few years.
The impact of Gaia reaches far into almost all of astronomy, and a
few examples will be given.

Masashi Hazumi (KEK) "LiteBIRD Satellite for Tests of Cosmic Inflation and Quantum Gravity"
2018-06-04 14:00 - 15:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Cosmological inflation is the leading hypothesis to resolve the problems in the Big Bang theory.
It predicts that primordial gravitational waves were created during the inflationary era, which
then imprinted large-scale curl patterns in the cosmic microwave background (CMB)
polarization map called the B-modes.
Measurements of the CMB B-mode signals are known as the best probe
to detect the primordial gravitational waves.
LiteBIRD is a candidate for JAXA’s strategic large mission to map the polarization of
the CMB radiation over the full sky at large angular scales with unprecedented precision,
which will offer us a crucial test of cosmic inflation. It will also serve as the first crucial test of
quantum gravity such as superstring theory. Precise polarization maps of LiteBIRD will also
provide us with valuable pieces of information on particle physics and astrophysics.
In this talk, I will give an overview of the science and design of LiteBIRD

Michael Hance (UCSC) "Searching for Compressed SUSY at the Energy Frontier"
2018-05-31 16:00 - 17:00
ABSTRACT:
Weak-scale Supersymmetry can help to resolve several puzzles presented by the Standard Model, including the nature of dark matter and the naturalness of the Higgs mass, and has motivated a robust search program at the Large Hadron Collider. Searches for direct production of Supersymmetric partners of weak bosons and leptons are particularly interesting as probes of dark matter and naturalness, but are challenged by small cross sections, low-momentum decay products, and multiple Standard Model backgrounds. I will review efforts by the ATLAS experiment to discover such new particles, with an emphasis on scenarios with “compressed” mass spectra containing nearly-mass-degenerate states. I will discuss recent LHC results, as well as prospects for discovery in Run 2 and beyond.

Nicholas Carlini (UCB) "Adversarial Machine Learning"
2018-05-29 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Many fundamental properties of neural networks are still not well
understood. This talk studies two of these from an adversarial perspective.
I begin with my main line of research and examine the apparently-fundamental
susceptibility of neural networks to adversarial examples. I develop effective
algorithms for generating adversarial examples and find that most most training
regimes are ineffective at increasing robustness. Then, I perform a brief
examination of neural network memorization, and demonstrate that training
data can be efficiently extracted from a trained model given only black-box
access to that model. I conclude with directions for future research.

Chris Fassnacht (UC Davis) "Cosmological parameters from strong gravitational lenses"
2018-05-17 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
Recent measurements of the Hubble Constant (H_0) through distance
ladder techniques have revealed a noticeable tension with the
Planck H_0 value that was obtained under the assumption of the cosmological
“standard model”, i.e., a flat Lambda cold dark matter cosmology. Is this
tension an indication that modifications to the standard model are
necessary, or is it the sign of unknown systematic effects in one or
both of the techniques? To address this question requires additional
high-precision measurements with techniques that are independent of
the distance ladder. The time delay strong lensing technique, in
which gravitational lensing by a massive galaxy produces multiple
images of a time-variable quasar, fulfills these requirements. I will
present recent results from the H0licow program, in which the analysis
of just three time-delay strong lenses has produced a 3.8% measurement
of H_0, and discuss the implications for other cosmological parameters,
including those describing dark energy. I will also discuss the
future prospects of this technique in the era of large sky surveys and
extremely large telescopes.

Christian Bauer (LBNL) "GENEVA: Combining perturbative calculations with parton showers"
2018-05-10 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
I will discuss the event generator GENEVA, which for the first time combines fixed order and resummed perturbative calculations with parton showering and hadronization. I will explain the basic physics concepts underlying GENEVA, and show how they can be used to achieve in principle any accuracy desired. After presenting physics results on the production of vector boson + jets at the LHC, I will finish by giving an overview of how to use GENEVA.

Alan Schwartz (University of Cincinnati) "Challenging the Standard Model with the Belle(II) Experiment"
2018-05-03 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The Belle experiment in Japan began taking data in the late 1990’s and went on to record the world’s largest sample of B-anti-B meson pairs produced in a quantum correlated state. This initial state allowed Belle, and the BaBar experiment at SLAC, to measure CP violation in B decays with high accuracy. These measurements contributed to the awarding of the 2008 Nobel Prize in Physics to Kobayashi and Maskawa for their theory of CP violation. However, other measurements have exhibited discrepancies with the Standard Model, e.g., measurements of |Vub| and |Vcb| , R(D) and R(D*), etc. Over the past several years, the Belle detector and accelerator complex have been rebuilt and significantly upgraded to become the Belle II experiment. Belle II is designed to record 50 times the data set that Belle recorded, and with much improved detector performance. This forthcoming data should resolve several discrepancies observed by Belle and BaBar. Here we review some recent results from Belle and discuss the physics program and current status of Belle II.

Gustavo Branco (CFTP-IST, Univ. de Lisboa, Portugal) - "Multi-Higgs Models, The Flavor Problem and the Origin of CP Violation"
2018-04-26 16:00 - 17:00
We analyse two-Higgs-Doublet extensions of the Standard Model, paying special attention
to novel mechanisms for natural suppression of scalar Flavor-Changing-Neutral-Currents
and their imllementation in specific models. Some of the most salient implications of these models will be presented. The possibility of having realistic models of spontaneous CP violation will be studied.

Paolo Calafiura (LBNL) HL-LHC Computing Challenges
2018-04-19 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
The current models for HL-LHC computing show order-of-magnitude resource shortages with large uncertainties. Business-as-usual is not an option unless we accept limiting HL-LHC physics reach, particularly for precision studies.
A grassroots initiative called the HEP Software Foundation has been collecting ideas and pooling efforts to perform the necessary R&D to meet these O($100M) resource shortages. HSF produced a Community White Paper that has been endorsed by the LHC experiments, the Worldwide LHC Computing Grid, and some funding agencies.
I will briefly review some of the technical and organizational challenges ahead of us as we turn the Community White Paper into a research program, and try to present some of the exciting new R&D ideas we are prototyping at Berkeley Lab and elsewhere.

George Smoot (UCB/LBNL) "Reinterpreting Low Frequency LIGO/Virgo Events as Gravitationally-Lensed Magnified Stellar-Mass Black Hole Mergers at Cosmological Distances"
2018-04-12 16:00 - 17:00
Abstract:
Though dismissed by most, we claim that strong gravitational lensing of the gravitational waves for merging black holes explains the high mass binary black hole mergers observed by LIGO/Virgo explains the apparent 30 M_Sun events better than any alternative models.
It turns out to be difficult to make large mass black hole binaries in sufficient number to explain LIGO’s results. However, strong gravitational lensing of cosmological distant mergers can naturally explain them while the redshift of the orbital frequencies amplifies the observed apparent masses.

Colin Hill (IAS) - "Fundamental Physics from the Foreground-Obscured Microwave Sky: Inflation, Neutrino Masses, and Beyond"
2018-04-05 16:00 - 17:00
The cosmic microwave background (CMB) remains a key source from which to extract information about fundamental physics, due to its clean, well-understood origin and immense constraining power on many types of new physics. The next decade of CMB observations will yield answers to at least two fundamental questions: (1) did large-field inflation source the initial density perturbations in our universe? (2) what is the absolute mass scale of the neutrinos? In this talk, I will explain the routes by which these answers will be obtained. Both rely on highly precise measurements of the polarization of the CMB, which can be used to search for the signature of primordial gravitational waves (answering the first question) and to measure the growth of cosmic structure via gravitational lensing (answering the second question). Moreover, I will describe new methods with which to overcome the most significant challenge to this program: emission from non-primordial foreground sources. I will highlight the major role that the Simons Observatory and CMB-Stage IV experiments will play in these exciting developments. Finally, I will describe additional unique information about the distribution and properties of baryons and dark matter that these measurements will yield, providing crucial feedback for cosmological analyses with DESI and other large-scale structure surveys.

Brice Menard (JHU) and Ting-Wen Lan (IPMU) - Twenty years of SDSS spectra: lessons for DESI
2018-04-03 16:00 - 17:00
We have played with SDSS spectra for almost two decades and enjoyed performing all sorts of statistical analyses with them. In this talk we will take a critical look at these explorations and discuss what has worked well and what has not, what mistakes were made and some of the fundamental limits arising from the calibration of the data — all of which are informative to prepare ourselves for the DESI era. Finally we will also discuss new data analysis ideas and emerging techniques that are likely to impact the way we think and manipulate spectra in the near future.

Sven Vahsen (University of Hawaii) - Directional Dark Matter Searches via Charge Cloud Tomography
2018-03-29 16:00 - 17:00
With WIMP-nucleon scattering limits approaching the neutrino floor, and coherent neutrino-nucleon scattering experimentally established, there is renewed interest in directional detectors as a means to penetrate the neutrino floor. The CYGNUS collaboration aims to deploy multiple gas Time Projection Chambers (TPCs) to accomplish this. I will review recent R&D work carried out within CYGNUS, with a focus on efforts at the University of Hawaii. I will discuss recently deployed directional neutron detectors capable of imaging the 3D surface shape of nuclear recoils with high resolution. These existing detectors represent a stepping stone towards larger detectors capable of providing fully tomographic 3D images of nuclear recoils. I will discuss how 3D recoil imaging is relevant to dark matter detection by enabling several new measurement techniques. Time permitting, I will also discuss a conceptual design study that compares the suitability of different technological approaches to a large-scale nuclear recoil observatory with sensitivity to both WIMP dark matter and neutrinos.

Lisa Barsotti (MIT) "Squeezing the most out of gravitational wave detectors"
2018-03-27 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
ABSTRACT:
The recent observations of gravitational waves have been enabled by a new generation of LIGO detectors, Advanced LIGO, the most sensitive laser interferometers ever built. In my talk I will review the main scienctific results from the first two Observing Runs, O1 and O2, and discuss the status of the Advanced LIGO detectors and plans for O3. I will also describe prospects for further extending the astrophysical reach of ground-based observations with future generations of detectors.

Andreu Font (U. College London) - "Cosmology with the Lyman alpha forest: challenges and opportunities”"
2018-03-22 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
From 2009 to 2014, the Baryon Oscillation Spectroscopic Survey (BOSS) used the SDSS telescope to obtain spectra of 1.5 million galaxies to get very accurate measurements of the Baryon Acoustic Oscillations (BAO) scale at redshift z ~0.5. At the same time, BOSS observed over 184 000 high redshift quasars (z>2.15) with the goal of detecting the BAO feature in the clustering of the intergalactic medium, using a technique known as the Lyman alpha forest (LyaF). In this talk I will overview the final results from the LyaF working group in BOSS, including the measurement of BAO at z=2.4 both from the auto-correlation of the LyaF (Bautista et al. 2017), and from its cross-correlation with quasars (du-Mas-des-Bourboux et al. 2017). From the combination of these studies we are able to measure the expansion rate of the Universe 11 billion years ago with a 2% uncertainty.
Starting in 2019, the Dark Energy Spectroscopic Instrument (DESI) will increase this dataset by an order of magnitude. In this talk I will review the challenges that we will face in order to provide an exquisite measurement of the expansion over cosmic history, and the opportunities that we will have to study other fundamental questions: the sum of the mass of the neutrino species, properties of dark matter particles, and the shape of the primordial power spectrum of density fluctuations.

Simone Ferraro (LBNL) "Lighting up the Dark Universe"
2018-03-20 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Recent progress in cosmological observations reveal a simple yet strange universe. Our preferred cosmological model relies on mysterious components such as Dark Matter, Dark Energy and an early period of accelerated expansion. The challenge in the next decade will be to understand the nature of these components and reveal new aspects of fundamental physics.
I will discuss the synergies between upcoming redshift and CMB experiments and show that thanks to sample variance cancellation techniques, a large improvement on constraining power is possible even at fixed volume. I will highlight the role of cross-correlations and velocity fields in increasing the statistical power of future surveys, while at the same time allowing for greater control of systematics. I will show how the combination of large-scale structure and CMB experiments hold great promise to reveal the secrets of our mysterious Universe.

Peter Mohr (NIST) "The New SI and Fundamental Constants"
2018-03-15 16:00 - 17:00 | 50-Auditorium
The International System of Units (SI) is expected to undergo a revolutionary change on
May 20, 2019. In October 2017, the International Committee on Weights and Measures met
at the International Bureau of Weights and Measures near Paris and recommended a new
definition of the SI such that a particular set of constants would have certain values when
expressed in the new SI units. In particular, the new SI would be defined by the statement:
The International System of Units, the SI, is the system of units in which

the unperturbed ground state hyperfine splitting frequency of the
caesium 133 atom Cs is 9 192 631 770 Hz,
the speed of light in vacuum c is 299 792 458 m/s,
the Planck constant h is 6.626 070 15× 10−34 J/Hz,
the elementary charge e is 1.602 176 634×10−19 C,
the Boltzmann constant k is 1.380 649×10−23 J/K,
the Avogadro constant NA is 6.022 140 76×1023 mol−1,
the luminous efficacy Kcd of monochromatic radiation of frequency 540×1012 hertz is 683 lm/W

The numerical values of the constants were determined by a special CODATA adjustment of
the values of the constants using data in papers that were accepted for publication by July
1, 2017.
The Convention of the Meter (Convention du M`etre), a treaty that specifies international
agreement on how units are defined, was established in 1875 with 17 nations initially signing
on, including the U.S. The SI, established within the treaty in 1960, is more recent and
continues to evolve. Currently, the treaty is agreed to by fifty-eight Member States, including
all the major industrialized countries. Even though a majority of people in the U.S. still
use units such as inches and pounds, the official standards for these units are based on the
SI units, so the U.S. national measurement standards will also be redefined, although the
change will be imperceptible in every-day use.
The redefinition will have a significant impact on the fundamental constants when ex-
pressed in SI units. Not only will the defining constants be exact, but many others will also
be exact, and still others will have considerably reduced uncertainties. This reflects a shift
from macroscopic measurement standards to quantum based standards.
This talk will describe the new SI, review reasons for the change, and show how units
can be based on assigned values of certain physical constants.

Julien Guy (LBNL) "The DESI Project, Construction Status and Prospects for Precise Cosmological Distance Measurements with Lyman-Alpha Forests"
2018-02-27 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The Dark Energy Spectroscopic Instrument is a multi-object spectrograph composed of a wide field corrector, a 5000 robotically positioned fiber system, and 10 3-arms spectrographs. The instrument is installed this year on the Mayall 4-m diameter telescope at Kitt Peak, Arizona. Operations will start next year. In 5 years, DESI will measure spectra and redshifts of more than 30 million galaxies and quasars. This catalog will be used to measure the expansion history of the Universe and the growth rate of structure in the past 10 billion years with sub-percent precision. I will present the construction status and give some insight on the Lyman-alpha BAO analysis.

Lauren Tompkins (Stanford U.) "The World’s most complicated game of Bingo: Pattern Recognition at the Energy-Intensity Frontier"
2018-02-20 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
In 2012 the ATLAS and CMS experiments discovered the Higgs Boson, firmly establishing the Standard Model as the dominant paradigm for subatomic particle interactions. Many expected the Higgs discovery to be one of several discoveries at the energy frontier, yet five years later it remains the single addition to the subatomic particle pantheon. Meanwhile, the LHC has begun to push the boundaries of the hadron collision intensity frontier, yielding large datasets for further understanding the Standard Model as well as continuing the increasingly difficult search for new physics. I will discuss a path through the intensity frontier, focusing on a hardware based, real-time pattern recognition engine which will enable the ATLAS experiment to fully exploit the delivered data by playing the world’s most complicated game of bingo.

Haichen Wang (LBNL) Title: The Higgs boson and the top quark share the stage
2018-02-15 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The top quark plays an important role in the collider phenomenology of the Higgs boson, and the study of the interplay between the top quark and the Higgs boson may provide key insights to some critical questions in particle physics. A milestone in the experimental study of the top-Higgs sector of the Standard Model will be the observation of the Higgs boson production in association with top quarks (ttH), a direct evidence for the top-Higgs Yukawa coupling. With 36.1 fb-1 pp collisions at 13 TeV, the ATLAS experiment performed searches for the ttH production in several channels and found the evidence for this production. In this talk, I start with a brief overview on the experimental understanding of the Higgs boson properties and motivate the study of the top-Higgs Yukawa coupling. I then present the ATLAS ttH searches with a focus on the diphoton channel. In the end, I discuss the prospect of the ttH study and its impact on other aspects of the LHC physics program.

Zeynep Demiragli (CMS / MIT) "Search for Dark Matter: CMS Strikes Back!"
2018-02-13 16:00 - 17:00 | HYBRID 50A-5132 (Sessler Conference Room), https://lbnl.zoom.us/j/91782268585, 50A-5132
Abstract:
The experiments at the Large Hadron Collider (LHC) at CERN are at the energy frontier of particle physics, searching for answers to fundamental questions of nature. In particular, dark matter (DM) presents strong evidence for physics beyond the standard model (SM). However, there is no experimental evidence of its non-gravitational interaction with SM particles. If DM has non-gravitational interactions with the SM particles, we could be producing the DM particles in the proton-proton collisions at the LHC. While the DM particles would not produce an observable signal in the detector, they may recoil with large transverse momentum against visible particles resulting in an overall transverse momentum imbalance in the collision event. In this talk, I will review the searches for DM particles in these missing momentum final states at the Compact Muon Solenoid (CMS) experiment. I will also discuss the prospects for discovering dark matter at the High Luminosity-LHC and other future experiments.
