LBNL Physics Division Research Progress Meetings

Special RPM - Rachel Mandelbaum (CMU) "Recent Progress and Future Prospects for Weak Lensing Cosmology""
2015-12-16 16:00 - 17:00 (America/Los_Angeles)
Abstract:
Measurements of weak gravitational lensing (coherent shape distortions of distant galaxies due to the lensing effect of mass between us and those galaxies) and are among the most promising ways to learn about the equation of state of dark energy, the theory of gravity on cosmological scales, and the connection between galaxies and the dark matter density field. In this talk, I will review the state of the field of weak lensing, including recent cosmological analysis and prospects with future surveys. I will then discuss some of the obstacles to robust weak lensing cosmology, such as the difficulty in estimating coherent galaxy shape distortions in real data, or in removing the effect of coherent galaxy shape alignments that arise due to (for example) large-scale tidal fields. After presenting recent progress on both of these sources of systematic uncertainty, I will conclude with future prospects for reducing them to below the statistical error and enabling robust cosmological constraints with future large surveys such as LSST, Euclid, and WFIRST.

Tomo Lazovich (Harvard) "One Higgs, Two Higgs, Old Higgs, New Higgs: the Higgs boson from discovery to new physics with the ATLAS experiment"
2016-01-12 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

The discovery of the Higgs in Run 1 of the LHC provided a more complete picture of the Standard Model and also gave particle physicists a new tool to use in the search for Beyond the Standard Model physics. With center of mass energy now at 13 TeV in LHC Run 2, we are poised to produce new resonances and probe higher energy scales. I will first discuss the challenging WW decay channel of the Higgs and how we went from discovery to the current best measurement of the Higgs cross section and observation of the vector boson fusion production mode. I will then discuss searches for new physics in both resonant and non-resonant production of two Higgs bosons in the 4b final state in Run 2, detailing the advantages and difficulties of using this final state to search for new physics over a wide range of masses.

Franz Elsner (UCL) "Parameter estimation in cosmology - The Planck likelihood"
2016-01-14 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
The inference of cosmological parameters requires the construction of a likelihood function that acts as an interface between theory and observational data. Using the CMB experiment Planck as a worked example, I provide an overview of the challenges associated with the analysis of high-resolution, state of the art experiments. In particular, I will discuss the approximations necessary to make an analysis feasible in practice, the role of nuisance parameters, and tests used to assess the robustness of the results. Reviewing the most important cosmological implications of Planck, I will conclude with an outlook of what we can expect to learn from future experiments.

Shawn Westerdale (PRINCETON) "Detecting Dark Matter with DarkSide-50"
2016-01-19 16:00 - 17:00 (America/Los_Angeles)
Abstract:
Dark matter constitutes 85% of the matter in the universe, yet despite its abundance, very little is known about it. One popular theory is that dark matter is made of Weakly Interacting Massive Particles, or WIMPs. Due to the low cross section for WIMP-nucleus interactions, the event rate of WIMPs in a detector is expected to be very low. This means that detectors must have extraordinarily low background rates and good background rejection in order to be able to detect these rare events above their background.
DarkSide-50 is a 50 kg liquid argon time project chamber, nested inside of a 30 tonne boron-loaded liquid scintillator neutron veto, which is inside a 1000 tonne water Cherenkov muon veto. Since neutrons can leave a signal identical to what is expected from WIMPs, neutrons are the most dangerous background to such an experiment. I will talk about the latest results from the DarkSide-50 detector, which recently published results from 120 days of running background free. This talk will also have a focus on the design and performance of the neutron veto system that enables the detector to remain free of neutron backgrounds by vetoing neutrons with > 99.2% efficiency.

Walter Pettus (YALE/WISCONSIN) "The DM-Ice Dark Matter Experiment"
2016-01-21 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
DM-Ice is a phased program towards the first direct detection search for dark matter in the Southern Hemisphere with a quarter ton scale NaI(Tl) crystal array. It will provide an understanding of the modulation signal reported by DAMA by running arrays at both Northern and Southern Hemisphere sites. A first generation experiment with 17-kg of active mass, DM-Ice17, was deployed in December 2010 at a depth of 2457 m under the ice at the geographic South Pole and has concluded its 3.5-yr primary physics run. An active R&D program is ongoing at the Boulby Underground Laboratory to investigate clean crystals and optimize detector components. A worldwide consortium of sodium iodide experiments is now preparing two 100-kg arrays to start data taking in 2016. I will report on the successes of the DM-Ice program and how the stage is set for definitively testing the DAMA signal anomaly.

Gaosong Li (Shanghai Jiao Tong University) - "Daya Bay Experiment"
2016-01-26 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
The Daya Bay Reactor Neutrino Experiment is designed to measure the neutrino mixing angle with unprecedented precision. The experiment utilizes multiple pairs of identical antineutrino detectors (ADs) at different baselines from three pairs of reactor cores to minimize systematic uncertainties. In 2012, Daya Bay made the first definitive measurement of a non-zero value for $theta_{13}$ using the first 55 days of data collected with six ADs by measuring the antineutrino rate deficit. With the final two ADs installed, Daya Bay resumed data taking in full 8-AD configuration in late 2012. More than 1 (0.15) million electron antineutrino candidates had been collected with the near (far) site detectors by the end of 2013, significantly improving the precision on . In addition to precision measurement of neutrino oscillation parameters, analyses exploring various other physics potential are carried out.
In this talk, I will focus on the calibration system. I will present calibration related works I have been working on to improve the detector absolute efficiency and neutrino oscillation analysis. I will also present the results on neutrino oscillation parameters from an independent analysis.

Frank Golf (UCSB) "Searching for New Physics with the Large Hadron Collider"
2016-02-04 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
After a two-year shutdown, the LHC restarted proton-proton collisions in 2015 with an increase in center-of-mass energy to 13 TeV. I describe some early results with data from the first year of running and plans for the significantly larger datasets that we expect to collect in the coming years.

Neal Dalal (Univ. Illinois at Urbana-Champaign) "Detecting Dark Matter Substructure Using ALMA"
2016-02-11 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
Dark matter halos surrounding galaxies are expected to contain copious substructure, in the form of gravitationally bound subhalos. Local Group observations suggest that our Galaxy has a deficit of substructure (the Missing Satellites Problem), possibly indicating new physics in the dark sector. I will describe how gravitational lensing may be used to measure the amount of dark substructure that exists in typical galaxy halos. In particular, I will explain how observations by the newly commissioned ALMA observatory of dusty galaxies from CMB surveys can probe halo substructure. I will show first results from our ALMA Cycle 2 observations, and argue that ALMA should be able to answer the Missing Satellites Problem in upcoming years.

Special RPM | Daniel Holz (U. Chicago) " Observation of Gravitational Waves from a Binary Black Hole Merger"
2016-02-18 08:00 - 17:00 (America/Los_Angeles)
We will provide an overview of LIGO’s first event. The signal is consistent with the merger of two black holes of ~30 Msun at a distance of ~400 Mpc. We will discuss some aspects of the detection, including parameter estimation, tests of general relativity, and astrophysical constraints.

Andreu Font-Ribera (LBNL) "Studying the Expansion of the Universe with Quasar Spectra"
2016-02-23 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
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 several 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 (Delubac et al. 2015), and from its cross-correlation with quasars (Font-Ribera et al. 2014). 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.
In the near future, the Dark Energy Spectroscopic Instrument (DESI) will increase this data set by an order of magnitude. DESI will provide an exquisite measurement of the expansion over cosmic time, while at the same time addressing other interesting questions: the sum of the mass of the neutrino species, properties of dark matter particles, tests of general relativity and the shape of the primordial power spectrum of density fluctuations.

Heather Gray (CERN) " Chasing Beauty: Probing the Higgs Using B-Quarks
2016-02-25 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
In the Standard Model, the Higgs has the highest probability to decay to b-quarks, yet this is one of the most challenging channels to observe at the LHC. I will explain the importance of measuring the coupling to the Higgs b-quarks, outline the ATLAS Run-1 H->bb analysis and review the current status of our knowledge of the coupling of the Higgs to b-quarks. I will also discuss how we might expect to observe the coupling of the Higgs to b-quarks during Run-2 of the LHC or in the future. Finally, I will discuss future measurements towards the Higgs self-coupling to explore the mechanism of electroweak symmetry breaking.

Mariarosaria D'Alfonso (CERN) "New Physics at LHC: Energy and Precision Frontiers"
2016-03-01 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

The evidence for the existence of dark matter in the universe is overwhelming; yet its exact nature, its mass(es) and coupling constants, are completely unknown. If kinematically accessible at colliders, these particles are expected to be produced directly or in the cascade of other new hypothetical particles. At the same time, the global fit to electroweak precision data impressively demonstrates the predictive power of Standard Model. Increasing the theoretical and experimental precision on electroweak observables may reveal inconsistencies between measurements and predictions due to the presence of new particles in the loop corrections. I will discuss a discovery physics program to take the full advantage of the ability of the LHC to probe the energy and the precision frontiers. I will highlight how improved scientific instruments with new possibilities will enable these searches.

Julien Guy (LPNHE) " The Prospects and Challenges of the Dark Energy Spectroscopic Instrument
2016-03-03 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract :
I will present the prospects of DESI for the measurement of Dark
Energy in light of a decade of efforts to unveil its nature, from the
discovery of cosmic acceleration with type Ia supernovae, to the most
recent results with supernovae and baryon acoustic oscillations (BAO).
DESI will map cosmic expansion up to redshifts of 3, anchoring
distances at low redshift to the era of past deceleration with an
order of magnitude gain in precision compared to current surveys.
DESI data will offer a stringent test of the standard model of
cosmology, with important possibilities for discovery.
The project, however, is not free from experimental challenges. I will
review the analysis efforts needed to extract the whole potential of
the BAO probe, from the optimization and calibration of the efficiency
of the redshift survey, to the characterization of the instrumental
noise in the Lyman-alpha forests.

Sho Uemura (Stanford) "The Heavy Photon Search Experiment at Jefferson Lab"
2016-03-08 16:00 - 17:00 (America/Los_Angeles)
Abstract:
The Heavy Photon Search (HPS) is a new experiment at Jefferson Lab searching for massive U(1) vector bosons (also known as heavy photons, dark photons, or A prime with a weak effective coupling to electric charge. The heavy photon is motivated as part of a hidden sector” model of dark matter, where it would mediate the self-interaction of dark matter and the interaction of dark and ordinary matter. HPS is sensitive to heavy photons of mass 10-500 MeV with coupling strength episilon squared of 1e-5 to 1e-10. The HPS experiment is designed to produce heavy photons in a process analoguous to bremsstrahlung using an electron beam on a fixed target, and detect decays to e+e pairs with two signatures (invariant mass resonance and displaced decay vertex). The detector is a compact, large-acceptance forward spectrometer comprising a silicon microstrip tracker for momentum measurement and vertexing and an electromagnetic calorimeter for triggering on e+e. Precise beamline controls, high-rate trigger and DAQ, and good time resolution are needed for a detector that comes within 0.5 mm of the beam and is sensitive down to 15 mrad from the beam plane, and must cope with the intense beam background in this environment. A low-mass tracker and clean track reconstruction are needed for the best sensitivity. This talk will describe the HPS experiment and its current status after test, commissioning, and engineering runs.

Shirley Ho (Carnegie Mellon University) " Joining Forces Against the Dark Universe: From the Cosmic Microwave Background to the Large Scale Structure"
2016-03-10 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

Despite tremendous recent progress, gaps remain in our knowledge of our understanding of the Universe. We have not yet pinned down the properties of dark energy, nor have we confirmed Einstein’s theory of Gravity at the largest scales.Current and upcoming large sky surveys of the Cosmic Microwave Background (CMB), Large Scale Structure (LSS) in galaxies, quasars and Lyman-alpha forest present us with the best opportunity to understand properties of the Universe.

I will first review recent cosmology results from CMB and LSS, concentrating on BOSS results using Baryon Acoustic Oscillations and Redshift Space Distortions. I will then introduce novel cosmological probes which combine CMB with LSS directly. These novel probes will open new windows into the momentum field of the Universe and Gravity at the largest scales. I will finally put these into the context of upcoming surveys such as Dark Energy Spectroscopic Instrument (DESI), Wide Field Infrared Survey Telescope (WFIRST) and CMB S4.

Dominick Olivito (CERN) "Searches for Dark Matter and Supersymmetry at 13 TeV with CMS"
2016-03-15 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

Results will be presented from searches looking for a large transverse momentum imbalance motivated by dark matter and supersymmetry, using a sample of proton-proton collisions collected at a center-of-mass energy of 13 TeV in 2015 with the CMS detector at the LHC. An inclusive analysis for hadronic jets and missing transverse momentum (MET), measured using the MT2 variable, will be covered, as well as an analysis searching for a pair of leptons with opposite-sign and the same flavor, hadronic jets, and MET. The latter analysis looks for one of two features in the mass spectrum of the lepton pair: either a resonance compatible with the Z boson mass or a kinematic edge. The results of each search are interpreted in simplified models of supersymmetry.

Michael Kagan (Stanford) "Exploring the TeV Energy Regime with Double Higgs Production at the LHC"
2016-03-17 16:00 - 17:00 UTC | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

The discovery of the Higgs boson by the ATLAS and CMS experiments at the Large Hadron Collider provides a novel tool to search for signs of physics beyond the Standard Model at the LHC. The Higgs boson is central to two frontiers in high energy physics today: the fundamental understanding of the mechanism for Electroweak Symmetry Breaking and for the generation of particle masses, and the exciting prospect of discovering new heavy TeV-scale particles interacting with the Higgs boson. Such new particles are predicted in theories of physics beyond the Standard Model which may incorporate additional symmetries or extra dimensions of space-time. In this talk, I will focus on how the search for di-Higgs boson production using the four bottom quark decay channel is central to probing both of these frontiers. I will discuss the critical developments in bottom quark identification that have enabled such searches for the first time. I will also discuss key advancements in high performance silicon pixel detectors and in new pattern recognition techniques inspired by cutting-edge machine learning and computer vision methods that are extending the future discovery potential at the LHC.

Simone Pagan Griso (LBNL) "Search for Supersymmetric Long-Lived Particles with the ATLAS Experiment"
2016-03-24 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
Supersymmetry is a well motivated extension of the Standard Model of particle physics,
although its realization in nature has yet to be proven.
The main efforts at the Large Hadron Collider to probe for supersymmetry
at the electroweak mass scale focus on the so-called “prompt” signatures.
In these cases, the super-symmetric partners of the known Standard Model particles
either decay close to the production point, within the detector resolution, or
traverse the detector with no strong interaction, leaving usually a large imbalance
of momentum in the transverse plane.
In this seminar I will focus on searches for supersymmetric particles
with a significant lifetime, that could be either directly or indirectly measured.
Such particles can easily evade current constraints based on prompt signatures.
After a brief introduction on the main mechanisms leading to long-lived
particles in supersymmetric theories, I will review the experimental techniques
employed in these searches using the ATLAS detector.
I will then present an overview of the data analysis results, with a particular focus on
the most recent ones.

Andrea Gabrielli, Michele Papucci, Zoltan Ligeti (LBNL) "Highlights from Morion EW and QCD"
2016-03-31 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

A brief overview of the main highlights discussed at Moriond 2016 is presented, with particular focus on LHC results, neutrino and flavour physics. One of the main topic of the conference is the first look at the results from LHC after its first run of 13 TeV proton-proton collisions ended last year. The experimental data confirm the Standard Model expectation concerning the vector boson, top and Higgs production rates. Searches for new resonances decaying into two photons in the ATLAS and CMS experiments have shown that the most significant deviation from the background prediction is observed at a diphoton invariant mass around 750 GeV. At the same time, the negative searches for signals of new phenomena decaying into other final state tightly constrained many new-physics scenarios, challenging previous theoretical wisdom and opening new perspectives in fundamental physics.

Chris Marshall (Univ. of Rochester) "Measurement of $K^{+}$ production by neutrinos at MINERvA"
2016-04-21 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
Charged kaon production by atmospheric neutrinos is a background in searches for the proton decay $p rightarrow K^{+} bar{
u}$. Measurements of neutrino-induced $K^{+}$ production are important inputs for current and future proton decay searches at Super-K, Hyper-K and DUNE. The MINERvA neutrino-nucleus cross section experiment at Fermilab uses timing information to isolate a sample of $K^{+}$ decay-at-rest events. I will present the first differential cross section measurements for both charged- and neutral-current $K^{+}$ production by neutrinos, and discuss how these measurements can be used to constrain background predictions for proton decay. I will also show the first experimental evidence for coherent $K^{+}$ production by neutrinos.

Giorgio Gratta (Stanford) "Probing Gravity - and Other Forces - at Extreme Scales"
2016-05-05 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
The inverse square law of gravity has been empirically tested to various degrees for distances between <0.1mm to 1AU. Outside this range very little is known and, yet, physics beyond the standard model may actually introduce new long-range forces that would be observed as anomalies in the 1/R^2 behavior of gravity. I will discuss some new experiments designed to substantially advance our knowledge in this area, at the two extremes of the distance range. While the long distance regime would involve a deep space mission, a new breed of experiments focusing on the micron regime is already taking data, not only on gravitational interactions.

Bharat Ratra (Kansas State U.) "Dark Energy: Constant or Time Variable? (...and other open questions)""
2016-05-12 16:00 - 17:00 (America/Los_Angeles)
Experiments and observations over the last two decades have persuaded cosmologists that (as yet undetected) dark energy is by far the main component of the energy budget of the universe. I review a few simple dark energy models and compare their predictions to observational data, to derive dark energy model-parameter constraints and to test consistency of different data sets. I conclude with a list of open cosmological questions.

Kathryn Zurek (LBNL/UCB) "New Ideas in Dark Matter Direct Detection"
2016-05-19 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:

Prof. V.M. Datar (Tata Institute of Fundamental Research, Mumbai, India) "The India based Neutrino Observatory project"
2016-05-31 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
The Indian effort to build an underground laboratory for rare processes is outlined. The flagship experiment, based on the 50 kiloton Iron Calorimeter, will measure atmospheric muon neutrinos and antineutrinos, separately, and will target the open problem of the neutrino mass hierarchy. Together with other experiments worldwide this will help address CP violation in the neutrino sector and this may help us understand why there is a preponderance of matter over anti-matter in the universe. The other experiments that are being planned are in the areas of: (1) neutrinoless double beta decay using a cryogenic bolometer of 124Sn (2) dark matter search and (3) a low energy accelerator for measuring nuclear cross sections of astrophysical interest.

David Stuart (UCSB) "Recent CMS SUSY Results"
2016-06-02 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
The LHC energy increase from 8 TeV to 13 TeV in 2015 provided a significant increase in sensitivity for new, high mass particles. This had a large impact on the sensitivity of searches for supersymmetric squarks and gluinos even though the 2015 data sample is relatively small. I will survey the results of these searches, discuss some of the strategy of the CMS SUSY program, and describe the methodology for three specific searches.

Kate Scholberg (Duke U.) "What Stubs and Sparkles Will Tell Us About Exploding Stars"
2016-06-23 04:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
When a massive star collapses at the end of its life, nearly all of
the gravitational binding energy of the resulting remnant is released
in the form of neutrinos. I will discuss the nature of the
core-collapse neutrino burst and what we can learn about particle
physics and about astrophysics from the detection of these neutrinos.
I will cover supernova neutrino detection techniques in general,
current supernova neutrino detectors, and prospects for specific
future experiments.

Alan Poon (LBL) "Searches for Majorana Neutrinos"
2016-06-30 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
Neutrino oscillation experiments have demonstrated conclusively that neutrinos have mass. In many Standard Model extensions neutrinos are favored to be Majorana fermions. A worldwide experimental program to search for this Majorana nature of neutrinos is underway. In this talk, I will review the status of experimental searches for Majorana neutrinos, with the focus on neutrinoless double-beta decay experiments.
I will also give a brief summary on GERDA Phase-II results that were released on June 29.

Joint Physics and ATAP Divisions Seminar | William Barletta (USPAS/ MIT) & Martin Breidenbach (SLAC) "Accelerator Research in the U.S. for High Energy Physics: A biased perspective"
2016-07-21 16:00 - 17:00 (America/Los_Angeles) | 50-Auditorium
Abstract:
The U.S. could move boldly toward accelerating transformational accelerator research for high-energy physics. Profound questions remain to be answered in particle physics; recent discoveries reconfirm the value of continued investments. However, going beyond the present generation of high energy accelerators will require changing the capability-cost curve of accelerators, which can only happen through an aggressive, sustained, and imaginative R&D program aimed at building the future accelerators at a dramatically lower cost. Both of us were members of Department of Energy panel that recently studied the potential structure of such a research program. We participated fully in the process and approve the report. Nonetheless, our experience led us to continue and extend our analysis of the issues that will drive accelerator research aimed at future accelerators for high-energy physics with the aim of informing interested physicists from all disciplines, not just accelerator experts. Broadly, we will look at prospects for proton-proton colliders and electron-position colliders – all interlaced with our biases and (and perhaps not politically correct) opinions.

Francois Bouchett (IAP) "Latest Cosmological News from the Planck Satellite Project"
2016-07-28 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
Sketched out in 1992, selected by ESA in 1996, and launched in 2009, the Planck satellite was shut off in 2013, after a measuring mission that exceeded all expectations. The Planck collaboration delivered a first set of cosmological data and results in March 21st 2013, and the full set in February 2015. Part of the data delivery is a “definitive” map of the anisotropies of the Cosmic Microwave Background (CMB), its angular power spectrum together with their full statistical characterization. The 2015 delivery further include pioneering polarisation data. I’ll briefly recall salient scientific results we derived from these data. The Planck collaboration is now working towards a “legacy release” by the end of 2016 which will mark the end of the formal collaboration we set up back in the previous century. To this end, we keep improving further our control on the potential level of residual systematics in the data and in accounting for these uncertainties in the final cosmological results to further enhance the robustness and precision of the constraints posed by Planck. For instance, we announced in May an improved likelihood analysis using detailed end-to-end simulation as well as an improved constraint on the reionization optical depth by using for the first time the E-mode polarisation data from the HFI instrument. This determination fully reconciles the CMB results with other astrophysical measurements of reionization from sources at high redshift. It also gives constraints on the level of reionization at redshifts beyond that of the most distant sources (z > 10). I will further give some perspectives on what is coming next.

Evan Pease (UCB/Yale) "New results from the 332-live-day exposure of the LUX dark matter experiment"
2016-08-02 16:00 - 17:00 (America/Los_Angeles) | Zoom Talk, 50A-5132, Berkeley, ca, 94720
Abstract:
Earlier this year the Large Underground Xenon (LUX) experiment completed its final dark matter search from 4850 feet below ground in the Sanford Underground Research Facility in Lead, South Dakota. Between September 2014 and May 2016 the LUX detector amassed 332 live days of exposure in its hunt for dark matter, primarily in search of Weakly Interacting Massive Particles (WIMPs), a favored dark matter candidate. Our analysis of this exposure yields improved and world-leading constraints on the interaction of WIMPs for a wide range of possible masses, placing a 90%-confidence exclusion limit on spin-independent WIMP-nucleon cross-section greater than 2.2 x 10^-46 cm^2 at 50 GeV/c^2 WIMP mass. This result includes a factor of 4 improvement over the previous LUX sensitivity to WIMP masses 100 GeV/c^2 and above. This presentation will include a discussion of changes in detector performance from the previous LUX search in 2013, a description of the “salted” data analysis approach, and a look at the frequent in-situ calibrations of the complex time-varying detector response during 20 months of operation.
