NPAC (Nuclear/Particle/Astro/Cosmo) Forum

RENO (Reactor Experiment for Neutrino Oscillation) is designed to measure the neutrino mixing angle theta_13 and the effective mass squared difference |dm^2_ee| using electron anti-neutrinos from six reactors at Hanbit nuclear power plant in S. Korea. RENO has been taking data since August 2011 using two identical detectors at near and far sites. The unprecedented measurement of the theta_13 by RENO was made in 2012 with 4.9 sigma significance using 220 live days of data.

In this talk we present the updated sin^2(2q13) value and first measurement on |dm^2_ee| based on a spectral shape analysis using 500 live days of data. And they are sin^2 (2theta_13) = 0.082 +- 0.009(stat.) +- 0.006 (syst.) and |dm^2_ee| = 2.62 +0.21 -0.23 (stat.) +0.12 -0.13(syst.) (X 10^-3 eV^2. The systematic uncertainty of sin^2(2q13) has improved mainly due to the better estimation of the Li9/He8 background and the reduction of its uncertainty. The 5 MeV excess of the electron anti-neutrino events is also discussed.
Host: 
Albrecht Karle
Speaker: Seon-Hee Seo Seoul National University

 

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Room and Building: 
5280 Chamberlin Hall
Over the past 15 years, gamma-ray observations have become a cornerstone of the rapidly expanding field of multi-messenger astronomy. Gamma-ray astronomy has helped revolutionize our view of the non-thermal universe and galvanized our search for the powerful natural particle accelerators found throughout the cosmos. These advances have relied on the capabilities of both the Fermi Gamma-ray Space Telescope (sensitive to energies between 30 MeV and 1 TeV) and the ground-based very high energy (VHE; E>85 GeV) gamma-ray observatories VERITAS, H.E.S.S., MAGIC, and HAWC.

Our progress has left us with as many new questions as we have answers. In the long term, these fresh questions may be addressed by next-generation observatories using new technology. However, much can be done now by expanding the capabilities of existing instruments and by more effectively combining data from the different observatories. I will outline a promising new approach that extends the reach of the gamma-ray observatory VERITAS while providing a natural context for combining data from multiple instruments. I will also consider the application of this approach to several of the field's outstanding questions and goals.
Host: 
Albrecht Karle
Speaker: Amanda Weinstein Iowa State University

 

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Room and Building: 
5280 Chamberlin Hall
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MINOS (Main Injector Neutrino Oscillation Search) is a long-baseline neutrino experiment that utilizes the Fermilab-based NuMI beam and two steel-scintillator tracking calorimeters to detect neutrino oscillation. Multivariate techniques allow the MINOS and MINOS+ col- laborations to exploit the νμ → νe dataset to produce limits on θ13, the CP-violating phase (δCP ), Non-Standard Interactions (NSI), and sterile neutrino oscillation parameters. Results encompassing standard three-flavor νe appearance and NSI are presented along with recent analysis developments regarding a sterile neutrino search in MINOS+.
Host: 
Albrecht Karle
Speaker: Adam Schreckenberger Univ. of Texas-Austin

 

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Room and Building: 
5310 Chamberlin Hall

After decades of study, the physical processes regulating star formation remain poorly understood. In particular, the role played by magnetic fields in both the formation of molecular cloud structure and the regulation of core collapse is unclear. In many simulations, magnetic fields dramatically affect both the star formation efficiency and lifetime of molecular clouds. However, observationally the strength and morphology of magnetic fields in molecular clouds remain poorly constrained. Submillimeter polarimetry provides an important observational window on magnetic fields in star forming regions. By mapping polarized emission from dust grains aligned with respect to their local magnetic field, the field orientation (projected on the sky) can be traced. The Next-Generation Balloon-borne Large Aperture Submillimeter Telescope (BLAST-TNG) is a 2.5 meter submillimeter polarimeter designed to map magnetic fields. BLAST-TNG utilizes three polarization-sensitive arrays of over 4000 microwave kinetic inductance detectors, centered at 250, 350, and 500 microns. BLAST-TNG will provide an unprecedented number of magnetic field vectors, and will enable a rigorous statistical analysis of the role that magnetic fields play in star formation. I will present the overall design and progress towards deployment of both the detector arrays and readout hardware in anticipation for a December 2016 BLAST-TNG Antarctic flight.

Host: 
Kam Arnold
Speaker: Brad Dober University of Pennsylvania

 

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Room and Building: 
5280 Chamberlin Hall

I will present the first observational estimate of the large-scale distribution of cosmic-ray (CR) nuclei in the halo of the Milky Way, achieved through gamma-ray observations of high- and intermediate velocity clouds by the Fermi Large Area Telescope. CRs up to at least PeV energies are usually described in the framework of an elementary scenario that involves acceleration by supernova remnants or superbubbles in the Milky Way disk, and then diffusive propagation throughout the Galaxy and its halo. The details of the propagation process are so far mainly constrained indirectly by the composition of CRs in the solar system, and then extrapolated to the whole Galaxy. The densities of CR nuclei in remote locations, on the other hand, can be traced via the gamma rays they produce in inelastic collisions with clouds of interstellar gas. Recently, we performed a search for gamma-ray emission from several high- and intermediate-velocity clouds located in the halo of the Milky Way up to ~ 7 kpc from the disk. The gamma-ray emission rate per hydrogen atom was found to decrease with distance from the disk, which provides direct evidence that CRs at the relevant energies originate therein. Furthermore, I will discuss how the results call for a critical reexamination of propagation models against other direct and indirect observations of CRs.

Host: 
Justin Vandenbroucke
Speaker: Luigi Tibaldo MPIK, Heidelberg

 

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Room and Building: 
4274 Chamberlin Hall
The High Altitude Water Cherenkov (HAWC) Observatory is a new ground-based TeV gamma-ray observatory operating in the high mountains of Mexico that is giving us a unique view of the high-energy sky. Its high sensitivity, wide field of view (~2 sr), and >95% uptime make it an ideal instrument for discovering gamma-ray burst (GRB) emission at ~100 GeV. Such a discovery would provide key information about the origins of prompt GRB emission as well as constraints on extragalactic background light models and the violation of Lorentz invariance. In this talk we will review HAWC performance and present results concentrating on our initial search for very high energy gamma-ray emission from GRBs with significant sensitivity to short transients with energies as small as 50 GeV.
Host: 
Stefan Westerhoff
Speaker: Joshua Wood University of Maryland

 

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Room and Building: 
5280 Chamberlin

The Atacama B-mode Search (ABS) was a crossed-Dragone telescope located at an elevation of 5200 m in the Atacama Desert in Chile that observed the cosmic microwave background (CMB) from February 2012 until October 2014. ABS was a pathfinder experiment that searched for the primordial B-mode polarization signal at large angular scales from multipole moments of l~40 to l~500, where it is expected to peak. The ABS focal plane consisted of 240 pixels sensitive to 145 GHz, each containing two transition-edge sensor bolometers coupled to orthogonal polarizations. Cold optics and an ambient temperature, rapidly-rotating half-wave plate made the ABS instrument unique. I will discuss the ABS instrument and its contributions to the field of CMB cosmology.

Host: 
Kam Arnold
Speaker: Sara Simon Princeton

 

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Room and Building: 
5280 Chamberlin Hall

Fast Radio Bursts (FRBs) are short (millisecond), non-repeating pulses that have now been observed at radio frequencies by three different radio telescopes. First detected a decade ago, a total of 16 of these events have been seen. I will report on the recent serendipitous discovery of an FRB at the Green Bank Telescope during a search for large-scale cosmic structure. The source is not resolved but our measurements of dispersion, Faraday rotation, and scattering along the line of sight leads us to conclude that the source is probably extragalactic and is located either in a dense, magnetized nebula associated with the source or a location within the central region of its host galaxy.

Host: 
Vandenbroucke
Speaker: Peter Timbie UW - Madison, Department of Physics

 

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Room and Building: 
5280 Chamberlin Hall

While the origins of the light (hydrogen, helium) and intermediate mass(carbon through iron) elements found in our solar system are well understood, we still don't know where roughly half of the elements heavier than iron were made. From the solar system abundance pattern of these nuclei, we can tell they were synthesized via rapid neutron captures in the r-process of nucleosynthesis. Exactly where the appropriate astrophysical conditions for the r-process exist, however, is still uncertain. Here we will discuss the two most popular potential astrophysical sites---core-collapse supernovae and neutron star mergers---and describe how progress in open issues in neutrino and nuclear physics may be the key to unlocking this longstanding mystery.

Host: 
Balantekin
Speaker: Rebecca Surman Notre Dame

 

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Room and Building: 
5310 Chamberlin Hall

In the last several decades neutrino oscillation experiments have given us a consistent picture of neutrino mass and mixing among three neutrino flavors. However, a series of longstanding and more recent anomalies hint at the existence of additional “sterile” neutrino flavors and complicates this simple picture. In order to improve on previous short baseline sterile neutrino searches, new detector technologies are required. Liquid Argon time projection chambers (LArTPCs) promise to have the sensitivity needed by current and next generation neutrino oscillation experiments looking for the appearance of electron-flavor neutrinos in a predominantly muon-flavored accelerator-based neutrino beam. MicroBooNE is the first of three LArTPC detectors planned for the newly re-established Short Baseline Neutrino program at Fermilab built to address the sterile neutrino hypothesis and to develop the technologies and expertise necessary to deploy a kiloton-scale LArTPC for future long baseline neutrino oscillation experiments. First data from the MicroBooNE experiment will be presented along with future prospects for LArTPC technology in the US.

Host: 
Baha Balantekin
Speaker: Matt Toups MIT

 

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Room and Building: 
5280 Chamberlin Hall

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