Bulletin of the American Physical Society
Mid-Atlantic Section Meeting 2021
Volume 66, Number 18
Friday–Sunday, December 3–5, 2021; Rutgers University, New Brunswick, New Jersey
Session C02: Nuclear, High Energy, and Particle Physics |
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Chair: Ethan Cline, Stony Brook University Room: 201B |
Saturday, December 4, 2021 9:00AM - 9:36AM |
C02.00001: Dark Photon Searches at Electron Accelerators Invited Speaker: Ethan Cline The search for an understanding of the elusive Dark Matter is one of the great scientific quests of our age. Recently there has been significant focus on a potential low mass ($<$1 GeV/$c^2$) mediator of a fifth force. The mediator, the so-called dark photon, has been the focus of several dedicated experiments. Recent discrepancies with the standard model such as the muon anomalous magnetic moment, and excesses in the invariant mass distribution of $e^+e^-$ pairs in decay of excited states of $^4$He and $^8$Be, further motivate the search for a low mass dark photon. In this talk I will discuss the status of several experiments which are searching for this carrier of the proposed fifth force, with a particular focus on APEX at Jefferson Lab, MAGIX at MESA, and the recently approved DarkLight experiment at ARIEL. [Preview Abstract] |
Saturday, December 4, 2021 9:36AM - 9:48AM |
C02.00002: Expanding the Search for Evidence of Nuclear Excitation by Electron Capture to New Nuclear/Atomic Systems C. J. Chiara, J. J. Carroll Nuclear excitation by electron capture (NEEC) is a coupled nuclear/atomic process by which the energy released during the capture of an electron into an atomic vacancy excites the nucleus of the atom to a higher-energy state. This phenomenon was proposed theoretically over 40 years ago [1], but the first experimental evidence was not forthcoming until much more recently [2,3], for the nucleus $^{93}$Mo. To expand our knowledge of NEEC beyond this single case, we performed an experiment similar to the successful one for $^{93}$Mo [2] to search for evidence of NEEC in the nucleus $^{127}$Cs. The T$_{1/2} \quad =$ 55-$\mu $s isomer in $^{127}$Cs was populated via the $^{9}$Be($^{123}$Sb, 5n) reaction; this isomer is a candidate for NEEC, with excitation possible to a level lying about 2 keV higher in energy. Considerations that went into the design of the experiment, and its subsequent implementation, will be discussed. \newline \newline [1] V. I. Goldanskii and V. A. Namiot, Phys. Lett. B \textbf{62}, 393 (1976). \newline [2] C. J. Chiara et al., Nature \textbf{554}, 216 (2018). \newline [3] C. J. Chiara et al., Nature \textbf{594}, E3 (2021). [Preview Abstract] |
Saturday, December 4, 2021 9:48AM - 10:00AM |
C02.00003: Radon removal from xenon via cryogenic distillation Sebastian Brunhart The nEXO experiment will utilize ultrahigh purity liquid xenon to search for neutrinoless double beta decay. Of particular concern for radioactive background control is radon-222, which will outgas into the xenon from all materials that are in contact with the xenon. To address this, cryogenic distillation is investigated as one of the options. Previous experiments have indicated that the xenon and radon can be separated in this fashion. A pilot still is currently being constructed at SLAC as further proof of concept for application in nEXO. This pilot will allow for the modeling of a high throughput column for the tonne-scale experiment. Analyses have been performed using the McCabe-Thiele method to predict the reduction factor of radon in the depleted distillate stream relative to the column feed flow rate, reflux ratio, and operating pressure. The results will be determined by measuring the activity of residual radon in a liquid xenon cell in a closed loop with the column. [Preview Abstract] |
Saturday, December 4, 2021 10:00AM - 10:12AM |
C02.00004: 10th Year Anniversary of Einstein's (Nonlocal) Hidden~Variables~and the Advancement of Science Manuel Morales Historically, when a new scientific discovery has been made it is necessary for others to test such findings for validity and if not invalid accept the new discovery by applying it towards the advancement of science. However, ten years has passed since the initial findings of the discovery of Albert Einstein’s (nonlocal) hidden variables was published and subsequently presented at an APS meeting in April, 2011. By accounting for two predetermined first-order functions, i.e., direct and indirect selection, unambiguous empirical evidence was obtained. Failure to account for the two mutually exclusive first-order variables necessary to conduct all empirical studies is a catastrophic omission leading to false-positive and false-negative results and conclusions. Fortunately, the two mutually exclusive origin functions are predetermined mechanisms such that it is necessary for their codes to be embedded in the empirical evidence generated by these variables. This means that the raw data in empirical investigations such as CERN’s LHC experiments contains the hidden codes of the fundamental variables that created their data. The discovery of these codes will reveal algorithms that can be applied towards the unification of physical theories and the advancement of science once the omission error issue has been addressed. [Preview Abstract] |
Saturday, December 4, 2021 10:12AM - 10:48AM |
C02.00005: Space-based Measurement of the Free Neutron Lifetime Invited Speaker: Jack Wilson Knowledge of the free neutron lifetime, $\tau_n$, is important as, along with other neutron decay parameters, it enables the determination of the quark-mixing matrix element $|V_{ud}|$ and therefore the testing of the unitarity of the CKM matrix. Additionally, uncertainties in $\tau_n$ dominate those in predictions of primordial $^4$He abundance from Big Bang nucleosynthesis. Historically, there have been two classes of high-precision experiments that measure $\tau_n$. ``Beam'' experiments measure the activation of a cold neutron beam passing through a volume capable of trapping the created protons or electrons. The second method is the more precise ``bottle'' technique that involves trapping ultra-cold neutrons and measuring their decay curves directly. However, a significant disagreement, currently $> 4.5~\sigma$, exists between the average results of these two techniques and has persisted for more than 15 years. This disagreement might be explained by an unidentified or improperly quantified systematic. However, given the direction of the disagreement the decay of neutrons to dark matter particles could also explain the observations. Recent analyses of data from the neutron spectrometers onboard NASA’s Lunar Prospector and MESSENGER spacecraft have demonstrated the possibility of using a third space-based technique that might one day break the stalemate. In this talk, I will review the neutron lifetime puzzle and the space-based measurements of $\tau_n$, describe the improvements made to the space-based technique and how it might be used in the future. [Preview Abstract] |
Saturday, December 4, 2021 10:48AM - 11:00AM |
C02.00006: A Track-Based Jet Finding Algorithm for the CMS Phase-2 Level 1 Trigger Samuel Leigh, Yuri Gershtein From early 2025 to mid 2027, the Large Hadron Collider (LHC) will undergo a series of upgrades which increases its collision rate. In its final form, the instantaneous collision rate of the collider will be 7.5 times its initial design value. This prompts the development of the Phase-2 Level 1 Trigger for the Compact Muon Solenoid (CMS) particle detector, which will decide in real-time which data from the upgraded LHC will be saved for further analysis. The focus of this talk is on the development of the firmware and software of a track-based jet finding algorithm, which is designed to run in real-time on a Field Programmable Gate Array (FPGA) board. This algorithm converts tracks (experimental signatures of quarks and gluons) into jets (collimated sprays of hadrons) through a nearest-neighbor clustering approach. The produced track-jets will be used to compute various quantities, such as $H_{T}$ and $H_{T}^{miss}$, which can be used by the Trigger for online event selection. We demonstrate that the algorithm is a valuable addition to the Trigger, exhibiting promising jet reconstruction performance. We also show that the firmware meets timing and resource constraints, and that we achieved an easily adjustable latency. [Preview Abstract] |
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