NPAC (Nuclear/Particle/Astro/Cosmo) Forum

The observation of neutrino oscillations is clear evidence for physics beyond the standard model. To make precise measurements of this phenomenon, neutrino oscillation experiments, including MiniBooNE, require an accurate description of neutrino charged current quasielastic (CCQE) cross sections to predict signal samples. Using a high-statistics sample of muon neutrino CCQE events, MiniBooNE finds that a simple Fermi gas model, with appropriate adjustments, accurately characterizes the CCQE events observed in a carbon-based detector. The extracted parameters include an effective axial mass, MA=1.23 +- 0.20GeV, that describes the four-momentum dependence of the axial-vector form factor of the nucleon, and a Pauli-suppression parameter, kappa=1.019 +- 0.011. Such a modified Fermi gas model may also be used by future accelerator-based experiments measuring neutrino oscillations on nuclear target.

Host: 
Teresa Montaruli
Speaker: Teppei Katori Indiana University

 

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Room and Building: 
4274 Chamberlin Hall

Nucleons in light nuclei have binding momenta smaller than the pion mass. In this energy regime, strong interactions can be described by effective field theories (EFTs) where all nuclear interactions are of contact type. I will discuss some of the features of these EFTs such as unusual renormalization leading to limit cycles, universal behavior in three-body systems, and a surprising amount of fine-tuning.

Speaker: Bira van Kolck University of Arizona

 

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Room and Building: 
4274 Chamberlin Hall

Reheating after inflation describes all the particle physics processes occurring from the decay of the inflaton up to the establishment of thermal equilibrium. Due to the strong model dependence, it is one of the most unknown stages in the history of the universe. It has been argued that SUSY flat directions are naturally excited during inflation, and that they slow down the thermalization of the inflaton decay products by providing a large effective mass to the fields they are coupled to. We discuss a nonperturbative decay channel for the flat directions which has been generally overlooked in the literature. It typically leads to a quick decay of the flat directions, and, consequently, to a suppression of their delaying effect for thermalization.

Speaker: Marco Peloso University of Minnesota

 

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Room and Building: 
4274 Chamberlin Hall
An observation of neutrinoless double beta decay would have profound consequences for our understanding of the lepton sector of the standard model. Double beta decay is only allowed if the neutrino and anti-neutrino are identical, which is a basic prediction of many extensions of the standard model, including many grand unified theories. Secondly, double beta decay could shed light on the scale of the neutrino mass spectrum. The EXO collaboration is developing sensitive searches for the double beta decay of Xenon-136. Our first experiment, EXO-200, is rapidly being constructed, and will be by far the largest double beta decay experiment ever attempted. We are also pursuing R&D to realize a system to tag the daughter barium nucleus of the decay using the techniques of single-ion spectroscopy. This would eliminate all conventional backgrounds, resulting in an ideal experiment.
Speaker: Carter Hall University of Maryland

 

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Room and Building: 
4274 Chamberlin Hall
Speaker: Xiangdong Ji (TBC) University of Maryland

 

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Room and Building: 
5280 Chamberlin Hall

The South Pole Telescope (SPT) is a 10 meter diameter millimeter wavelength telescope located at the South Pole. It's primary science project is to conduct a 4000 square degree survey to find clusters of galaxies via the Sunyaev-Zel'dovich (SZ) effect, the inverse Compton scattering of the CMB off of hot intra-cluster gas. An SZ survey of this size should find several thousand galaxy clusters, which can in principle place interesting constraints on the dark energy density and equation of state, as well as produce a host of other secondary science results (e.g. - measurements of small scale primary and other secondary CMB anisotropies, gravitational lensing of the CMB, point source catalogs at millimeter wavelengths, ...). To achieve this required over an order of magnitude increase in mapping speed over previous generation millimeter wavelength receivers, and was accomplished with the development of a 960 element large format bolometer array. I will discuss the design and construction of the SPT receiver, SPT's current project status, which recently began its second year of observations, and future plans for the SPT.

Speaker: Bradford Benson UC Berkeley

 

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Room and Building: 
4274 Chamberlin Hall

String theory has been around for over 30 years. The string vacuum determines the spectrum of states and gauge interactions of the low energy theory. Some talk about on the order of 10^{300} vacua for string theory, BUT to date there are only a handfull of candidate vacua which look anything like our observed low energy world. In this talk I will discuss a new strategy for finding the minimal supersymmetric standard model in the immense string landscape.

Speaker: Stuart Raby Ohio

 

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Room and Building: 
4274 Chamberlin Hall

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