LBNL Physics Division Research Progress Meetings

Miland Diwan (Brookhaven National Laboratory), "Challenges and Opportunities for a Long Baseline Neutrino Experiment "
2015-09-24 16:00 - 17:00 UTC | ca
Title: Challenges and Opportunities for a Long Baseline Neutrino Experiment
Abstract: Neutrino mass and mixing is one of the few indications of new physics beyond the standard model, and new theoretical and experimental work is needed to understand neutrino properties and their role in the Universe as the most abundant particle of matter. I will briefly review the current state of understanding of neutrinos properties. I will then describe the current optimization for the Fermilab based LBNF/DUNE program focusing on most important technical challenges.

Benjamin Schmidt (KIT, Germany) "Background discrimination capabilities and recent results of the EDELWEISS-III direct dark matter search experiment"
2015-09-22 16:00 - 17:00 (America/Los_Angeles)
Abstract:
The EDELWEISS collaboration is operating a large set of 36 massive cryogenic Ge detectors for the direct detection of Weakly Interacting Massive Particles (WIMPs) in the underground laboratory of Modane, France (LSM). The twofold detector readout in ionization and phonons allows a discrimination between nuclear recoils from the scattering of neutrons or WIMPs and electron recoils from the scattering of γ- and β-particles. As part of the R&D for the current data taking in EDELWEISS-III a new data analysis framework has been developed and evaluated on a dedicated commissioning run. Results on the surface event rejection of the detectors with advanced electrode design (FID) from this data-set will be presented. WIMP search data taking has been ongoing since August 2014 and the latest results of a low mass WIMP analysis will be discussed.

Walter Hopkins - Using Direct Stop Searches at ATLAS to Constrain the Parameter Space of Supersymmetric Models
2015-09-01 16:00 - 17:00 (America/Los_Angeles)
Abstract:

A summary of the search for direct stop production in the 0-lepton channel is presented using 20 TeV data collected with the ATLAS experiment at the LHC. One of the stop decay modes considered is a stop decay to a top and a neutral lightest supersymmetric particle (LSP) resulting in signature with four or more jets and large missing energy. No excess is observed above the background expectation and limits are set on the stop and LSP masses and are presented as a function of stop decay branching fraction, combining the results from the 0 and 1-lepton channels. Additionally, the results are interpreted to confine the much larger parameters space of a more general supersymmetric model. Finally, outlook for stop searches for the LHC Run 2 will also be discussed.

Lifan Wang (Texas A&M)
2015-05-21 16:00 - 17:00 (America/Los_Angeles)
Title: The Latest Development of Optical/NIR Astronomy at Dome A, Antarctica
Abstract:
Dome A, the highest spot on Antarctic plateau is likely the best site for ground-based astronomy. I present in this talk an update on the recent progresses in building an astronomical observatory at Dome A. In the near term, the 68cm wide field Antarctic Survey Telescopes (AST3) will be collecting data that are continuous for more than 3 months during the Antarctic winter. A time-domain study in the NIR of supernovae and other transients will be enabled by an infrared version of AST3. We expect the AST3 data to be unique in terms of their time coverage. In the longer term, we expect to build one 2.5 meter optical/NIR telescope and one 5 meter THz telescope, and use these telescopes to discover supernova explosions at redshift far beyond what is possible with a conventional temperate telescope.

Jennifer Thomas (UCLA; Univ. of Wisconsin) " Cheap as CHIPS - Large Water Cherenkov Detectors: Faster and Cheaper"
2015-04-30 16:00 - 17:00 (America/Los_Angeles)
Title: Cheap as CHIPS – Large Water Cherenkov Detectors: Faster and Cheaper
Abstract:
CHIPS is an R&D program focused on designing and fabricating a cost-effective large water Cherenkov detector (WCD) to study neutrino oscillations. Traditional WCD’s with a low energy threshold have been built in special large underground caverns. Civil construction of such facilities is costly and the excavation phase significantly delays the detector installation although, in the end, it offers a well-shielded apparatus with versatile physics program. Following concepts developed for the LBNE WCD (arXiv:1204.2295), we propose to submerge a detector in a deep water reservoir, which avoids the excavation and exploits the directionality of an accelerator neutrino beam for optimizing the detector. Following the LOI (arXiv:1307.5918), we have submerged a small test detector in a mine pit in Minnesota, 7 mrad off NuMI axis. Borrowing technical ideas and solutions from IceCube and KM3Net, we are now focusing on designing a large (10-20kt) isolated water container to house photodetectors with underwater readout and triggering. We will describe the CHIPS concept and its physics potential in more detail, and will present the ongoing R&D activities.

Brian Hamilton (Univ. of Maryland) "New Results from LHCb"
2015-04-23 16:00 - 17:00 (America/Los_Angeles)
Title: New Results from LHCb
Abstract:
I will present several new results based on the full dataset collected by the LHCb detector during the 2011 and 2012 running periods. In particular, the first measurement from LHCb of the magnitude of the CKM matrix element Vub via semileptonic decays of the $Lambda_{b}$ baryon and its impact on contributions of right handed currents will be discussed. I will also present new results on the electroweak penguin decay $B to K^{*} mumu$ and the status of anomalies in this channel observed in the previous analysis which used a subset of the full data. Plans for the LHCb experiment during Run 2 of the LHC and beyond will also be discussed.
