Bulletin of the American Physical Society
2019 Annual Meeting of the APS Far West Section
Volume 64, Number 17
Friday–Saturday, November 1–2, 2019; Stanford, California
Session H03: High Energy and Nuclear Physics |
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Chair: Alessandra Lanzara, University of California, Berkeley Room: Science Teaching and Learning Center STLC 118 |
Saturday, November 2, 2019 3:30PM - 3:42PM |
H03.00001: The Light Dark Matter eXperiment Omar Moreno The Light Dark Matter eXperiment (LDMX) proposes a high-statistics search for low-mass dark matter in fixed-target electron-nucleus collisions. Ultimately, LDMX will explore thermal relic dark matter over most of the viable sub-GeV mass range to a decisive level of sensitivity. To achieve this goal, LDMX employs the missing momentum technique, where electrons scattering in a thin target can produce dark matter via ``dark bremsstrahlung'' giving rise to significant missing momentum and energy in the detector. To identify these rare signal events, LDMX individually tags incoming beam-energy electrons, unambiguously associates them with low energy, moderate transverse-momentum recoils of the incoming electron, and establishes the absence of any additional forward-recoiling charged particles or neutral hadrons. LDMX will employ low mass tracking to tag incoming beam-energy electrons with high purity and cleanly reconstruct recoils. A high-speed, granular calorimeter with MIP sensitivity is used to reject the high rate of bremsstrahlung background at trigger level while working in tandem with a hadronic calorimeter to veto rare photo-nuclear reactions. This talk will summarize the small-scale detector concept for LDMX, ongoing performance studies, and near future prospects. [Preview Abstract] |
Saturday, November 2, 2019 3:42PM - 3:54PM |
H03.00002: Simulations of Photonic Band Gap Resonators for HAYSTAC Mirelys Carcana Barbosa, Samantha M. Lewis, Karl van Bibber The Haloscope at Yale Sensitive to Axion CDM (HAYSTAC) searches for the axion, a promising dark matter candidate, using a microwave resonator in a magnetic field to convert the axions into detectable photons. To search for axions, we tune the detector to a specific frequency in an attempt to match the electromagnetic cavity mode with the mass of the axion. The operating mode is the TM010. However, many cavity modes are supported, leading to mode crossings that reduce our ability to collect data. As a result, the useful tuning range of the cavity is limited. We are developing a tunable Photonic Band Gap (PBG) resonator to eliminate these mode crossings. PBGs consist of rods arranged in a lattice that allow us to isolate particular modes at desired frequencies while not supporting unwanted modes. This work will provide an overview of PBG development for HAYSTAC and give an update on the testing of the prototype design. [Preview Abstract] |
Saturday, November 2, 2019 3:54PM - 4:06PM |
H03.00003: The Heavy Photon Search Experiment Cameron Bravo The Heavy Photon Search (HPS) experiment searches for an electro-produced dark photon using an electron beam provided by the CEBAF accelerator at the Thomas Jefferson National Accelerator Facility. HPS has successfully completed two engineering runs. In 2015 using a 1.056 GeV, 50 nA electron beam, 1.7 days (10 mC) of data was obtained and 5.4 days (92.5 mC) of data was collected in 2016 using a 2.3 GeV, 200 nA electron beam. In addition, HPS has completed its first physics run in the summer of 2019. HPS looks for dark photons through two distinct methods, a resonance search in the $e^{+}e^{-}$ invariant mass distribution above the large QED background and a displaced vertex search for long-lived dark photons. HPS employs a compact spectrometer, matched to the forward kinematic characteristics of A$^\prime$ electro-production. The detector consists of a silicon tracker for momentum analysis and vertexing and a lead tungstate (PbWO$_4$) electromagnetic calorimeter for particle ID and triggering. Both analyses are complete for the 2015 engineering run and demonstrate the full functionality of the experiment that will probe unexplored parameter space with more luminosity. Results from the 2015 daset will be presented as well as an update on 2016 analysis and the 2019 physics run. [Preview Abstract] |
Saturday, November 2, 2019 4:06PM - 4:18PM |
H03.00004: Progress in the Design of a High-Gradient, THz-Driven Electron Gun Samantha Lewis, Mohamed Othman, Emilio Nanni, Sami Tantawi High energy particle sources are in demand for a variety of applications. To limit the size and cost of these sources, high accelerating gradient is required. Vacuum breakdown limits the achievable gradient in normal conducting accelerators, but using THz-frequency structures could allow for compact, GV/m-scale devices. This work will present the design of standing-wave electron guns which utilize this principle. The gun cavities are machined from copper and operate in the pi-mode at 110 GHz. In the current design, electrons are field-emitted from a diamond cathode and accelerated to 400 keV in 2 mm. The device will be tested using a pulsed 110 GHz gyrotron in order to characterize the electron beam properties and collect breakdown statistics. Future designs will also be discussed, including a Cu cathode and possibilities for reaching 1 MeV. [Preview Abstract] |
Saturday, November 2, 2019 4:18PM - 4:30PM |
H03.00005: Status of the ALICE Fast Interaction Trigger (FIT) Hardware and Simulations Joseph Crowley The ALICE experiment at the Large Hadron Collider studies collisions of relativistic heavy ions to learn about matter with the highest energy densities in the universe: the quark-gluon plasma. The Fast Interaction Trigger (FIT) is a detector upgrade that will determine the minimum bias trigger, event multiplicity, centrality, collision time, event plane, and beam luminosity for ALICE. Simulations to estimate the efficiency and acceptance of ALICE detectors are implemented in the Online-Offline O\textasciicircum 2 computing framework. This summer, the FIT T0 (FT0) detector geometry was developed in ROOT for O\textasciicircum 2 Monte-Carlo simulations, including the aluminum frame that holds the FT0 detector, which will contribute to the backgrounds for other detectors due to photon conversion and secondary particle production. Hardware for the FT0 C-side was assembled and tested at CERN, and it is now ready for installation. This talk will present the status of the hardware and software for the FIT T0 detector that will be used in the LHC for Run 3. [Preview Abstract] |
Saturday, November 2, 2019 4:30PM - 4:42PM |
H03.00006: Detector simulation in the O\textasciicircum 2 upgrade to the ALICE experiment Ryan Nevils The ALICE experiment at the LHC is currently undergoing upgrades to prepare for Run 3 in 2020. One aspect of these upgrades is the ``Online - Offline computing system'' (O\textasciicircum 2), which is an upgrade to the computing facilities of ALICE as well as the underlying software to accommodate the high data rates and volumes. Part of the software upgrade involves creating models of the detector components, so that the collision events can be simulated. These simulations will help validate the detector's performance. This talk will present an overview of O\textasciicircum 2 as well as the modeling of the ALICE Fast Interaction Detector (FIT) in software. [Preview Abstract] |
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