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• CMS MTD is important for an expanded physics reach : we expect 20- 25% effective luminosity increase in crucial precision Higgs measurements. • Our project is significantly advanced – the sensor performance is close to specification. • We are heavily involved in efforts to ensure 30 ps time resolution for sensors throughout the HL-LHC run.
The Daya Bay reactor neutrino experiment studies the disappearance of electron antineutrinos from reactor cores at the Daya Bay Power Plant located in China. Daya Bay has made a precision measurement of one of the parameters describing the quantum mechanical mixing between neutrino flavor states and mass states, the mixing angle $\theta_{13}$. One source of systematic uncertainty in the measurement is due to background induced by cosmic ray muons. The detectors are located underground to minimize the cosmic flux, but the residual backgrounds must be measured. This program will focus on the study and measurement of the cosmic muon-induced backgrounds at Daya Bay with a goal of achieving the lowest possible level of background-related systematics on the disappearance measurement. In addition to providing crucial input to the Daya Bay disappearance analysis, measurements of the muon flux and the production of neutrons and radioactive nuclei by cosmic muons will be of general interest to other underground experiments such as double beta decay and dark matter searches.
Despite the correct and consistent description of the elementary particle interactions, there is evidence that the Standard Model (SM) is an incomplete theory. Solving the issues faced by the SM requires the introduction of new interactions and, if such interactions exist, they can be observed as deviations in the SM predictions or forbidden processes. Particularly of interest for this work are the B$^0_s$ mesons and $\tau$ leptons produced in the DØ and Belle II experiments, respectively, where the luminosity provides the statistics for high precision SM measurements and searches for new physics. In this work, the lifetime measurement of the B$^0_s$ meson in the decay channel $B^0_s \to J/\Psi f_0(980)$ is reported, which is a CP-odd final state. Using 10.4 fb$^{-1}$ of data collected with the DØ detector in Run II of the Tevatron, the lifetime of the CP-odd component of the B$^0_s$ meson is measured to be $\tau(B^0_s)$ = 1.70$\pm$0.14 (stat)$\pm$0.05 (syst) ps. This measurement is closely related to the $B^0_s - \bar{B^0_s}$ mixing and searches for new CP violation mechanisms. Additionally, the $\tau$ lepton physics program of Belle II is reviewed and two sensitivity studies are shown: (i) $\tau^- \to \eta \pi^-\pi^0 \nu_{\tau}$, which in the isospin symmetry limit SU(2) is a cross-check of consistency with the cross section $\sigma(e^+e^- \to \eta \pi^+ \pi^-$) at low energies; (ii) $\tau^- \to \eta \pi^- \nu_{\tau}$, which has never been observed and, given the suppression by G-parity, it allows the searches of scalar and tensor interactions. Estimations from 1 to 20 ab$^{-1}$ are shown, corresponding to the integrated luminosity expected during the first years of operation of Belle II.
Positive thermal expansion can cause significant stress or even catastrophic device failure in applications where materials are placed in confined environments. At material interfaces such as coatings, thermal expansion effects can also lead to cracking and peeling behavior. The ability to impart controlled thermal expansion properties in an array of designs via additive manufacturing technologies would mitigate such problems and bring significant value to various materials science and engineering challenges. Negative thermal expansion materials are of interest for composite material applications whereby they can compensate for the behavior of a positive thermal expansion matrix. This Truman Fellowship LDRD research project presents complimentary experimental and molecular modeling results towards the fundamental understanding and development of metal-organic framework (MOF) materials with controlled thermal expansion properties. Design strategies for imparting precisely tailored negative, zero, and positive thermal expansion regimes in MOFs are studied and the implications of these design strategies for the use of MOFs as an emergent negative thermal expansion material class are examined. Challenges towards exploiting this nanoscale behavior at length scales relevant to composite material systems are introduced. ACKNOWLEDGEMENTS I will be forever grateful to the Truman Fellowship Selection Committee for providing me with the opportunity to pursue this research project. The unique opportunity to carry out this exciting scientific research with all of the resources and support that Sandia has to offer has been a truly rewarding experience. I would like to especially thank Yolanda Moreno for her endless assistance throughout my time as a Truman Fellow. It is hard to imagine a more supportive and stimulating scientific environment to carry out this research. I would also like to thank all of my colleagues and the individuals that have collaborated with me throughout this Fellowship, both internal and external to Sandia. Many of you appear as co-authors on the publications resulting from this LDRD, including especially fruitful collaborations with researchers at the Georgia Institute of Technology and the University of Amsterdam. I cannot express enough my gratitude for the significant role that you all played in shaping my educational experience and the success during my time at Sandia as a Truman Fellow.
In an X-ray free-electron laser (XFEL), a high quality relativistic electron beam from a linear accelerator traverses an array of undulator magnets to generate a high power X-ray beam by allowing the FEL to reach saturation. In many XFELs, phase shifters haven’t been commonly used or included in their designs. The importance of the phase shifter was recognized only recently. A phase shifter can be constructed using either an electromagnet (EM) or a permanent magnet (PM). EM phase shifters are heavy, complex to operate, and take more valuable longitudinal space between the undulators. Compared to EMs, the PMs have several outstanding advantages, including compactness, lighter weights, simple operation, and low maintenance. This project has developed an innovative design of fixed-gap, tunable PM-based compact phase shifter for the XFEL. While keeping the poles and gap fixed, the new design incorporates proven features from the prior work, along with novel field tuning methods, which allow the field strength to be adjusted within a reasonably large range to achieve the desired range of the phase delay control. The PM design without electric currents and power electronics associated with EMs improves reliability by reducing the number of possible points of failure and lowers the operation cost. The compactness makes it possible to use PM phase shifters in the existing XFELs with small gaps between adjacent undulators, as well as in the new XFELs without significantly increasing the FEL length. In Phase I we have accomplished the followings; 1) determined the optimum physics parameters for both weak and strong phase shifters; 2) conducted magnetic design with concrete magnetic and geometrical parameters of actual produced PM materials; 3) provided solutions to achieve precision fine tuning of the magnetic fields with unique methods; 4) elaborated a design based upon ease of manufacturing and cost analysis; and 5) produced rare-earth PM materials, which will be used for prototyping in Phase II. The phase I results provide a foundation for the research and development in the Phase II project, which will aim at building two full-size PM phase shifters and testing at SLAC National Accelerator Laboratory. This project will significantly provide the potential to bring a paradigm change in accelerator technology, replacing conventional electromagnets for many existing accelerator applications and allowing the development of new applications in completely new areas. For example, the PM FEL phase shifters can help significantly improve coherence and power of an XFEL. The proposed use of PM phase shifters will also bring significant cost savings to the construction, operation and maintenance of FEL facilities.
The electromagnetic form factors are fundamental quantities characterizing the internal structure of the nucleon. Their measurements have provided significant insight into the spatial distribution and interaction of quarks inside the proton. The knowledge of high Q2 form factors proves essential in understanding the properties of quantum chromodynamics in the transition region from non-perturbative to perturbative behavior. It also provides important links to generalized parton distributions, which describe the three-dimensional structure of hadrons at the parton level. In view of the significant theoretical research activities in this field, high quality experimental data are crucial for providing stringent tests and benchmarks to guide and test different models. The form factors can be accessed in experiments by measuring elastic scattering of electrons off a hydrogen target. Experiment E12-07-108, which took place at the Thomas Jefferson National Accelerator Facility, conducted precise measurements of the unpolarized e-p elastic scattering cross section over a Q2 range of 0.6-16.5 GeV2 . This thesis presents the results for 7 kinematic settings with total uncertainties that are 1.5 times smaller than those of the existing data at large Q2 . The proton magnetic form factors were extracted using a parameterization of the form factor ratio obtained from recent polarized e-p scattering experiments. Comparisons to existing global and phenomenological fits are presented.
The ETROC (Endcap Timing Readout Chip) is being developed for the LGAD-based CMS Endcap Timing Layer (ETL) at HL-LHC. The ETL on each side of the interaction region will be instrumented with a two-disk system of MIP-sensitive LGAD silicon devices to be read out by ETROCs for precision timing measurement with down to 30 ps timing resolution. The ETROC is designed to handle a 16 x 16 pixel cell matrix, with each pixel cell being 1.3 mm x 1.3 mm to match the LGAD sensor pixel size. Approximately 15% of the sensors near the highest eta region will experience hadron fluence above 1e15 neq/cm² towards end of operation of HL-LHC, resulting in small signal amplitude with LGAD gain reduced to around 10. For this reason, the front-end design for preamplifier and discriminator has been specifically optimized for the reduced LGAD signals, with enough flexibilities to meet the ETL specific needs for time resolution, power budget and radiation profile.
Elastic electromagnetic form factors characterize the distribution of electric charge and magnetization current inside the nucleon and reflect the internal structure determined by Quantum Chromodynamics. Existing data on the proton magnetic form factor at high Q2 (the 4-momentum transfer squared) have large statistical and systematic uncertainties. The GMp experiment E12-07-108 was one of the first set of experiments to run in Hall A at Jefferson Lab after the 12 GeV upgrade with the goal of this experiment to precisely measure the electron-proton elastic cross section for Q2 up to 17 GeV2 with an accuracy of better than 2% - several times better than existing data in this Q2 range. This will allow further tests of form factor scaling predicted by pQCD and, additionally, will be an important benchmark for many other experiments where elastic electron-proton scattering is used for normalization. Since, GMp data were taken at lower ?(virtual photon polarization) than SLAC data, the measured cross sections recieve a smaller contribution from the electric form factor. This dissertation analyzed the GMp experiment data for five different kinematic settings determining the form factor with total uncertainties nearly two times smaller than the existing data at these Q2. This dissertation also presents the results of all Fall 2016 and Spring 2016 GMp experiment data. The proton magnetic form factors were extracted using both the Rosenbluth separation method and a parameterization of the form factor ratio (?pGpE=GpM) obtained from a fit to the existing cross section data. At the end of this thesis, the extracted GMp form factor data is compared to the existing data. The results for ?pGpE=GpM from Rosenbluth separations are found to be consistent with previous extractions, but with significantly reduced uncertainties, further highlighting the discrepancy with the polarization transfer technique. This data set can provide significant additional constraints on contributions from two-photon exchange.
Continuing with our effort of precisely measuring the branching ratios for long-lived fission products we have collected and measured two radiopure ¹⁵⁶Eu samples. The samples were collected on thin (40 μg/cm²) carbon-foil backings using a low-energy mass-separated beam of A = 156 fission products from CARIBU at Argonne National Laboratory. During collection, a HPGe detector was used to continuously monitor the implantation rate by detecting the characteristic γ rays emitted following the β decay of the shorter-lived fission products. The first sample had measured activity of 375 Bq while the second one had an activity of 700 Bq. The implanted samples were then shipped to Texas A&M University for measurement of the subsequent decay.
1. Accuracy and precision of measurements: Case study of DARHT-1 E-dot and Energy Spectrometer; Operations oriented. 2. Type of measurements: Case study of DARHT-2 Beam-Target Interactions (the “low-hanging fruit” metric); Research oriented.
Y-12 has successfully established the processes and procedures required to obtain subsamples from NNMA sample materials and then package/ship them to DOE national laboratory analytical laboratories for high precision analyses
This article is set during the 1944 and 1945 final push to complete Project Y—the Manhattan Project at Los Alamos—and focuses primarily on overcoming the challenge of creating and demonstrating a successful convergent explosive implosion to turn a subcritical quantity of plutonium into a critical mass. The critical mass would then efficiently yield kilotons of trinitrotoluene (TNT)-equivalent energy in about a microsecond, demonstrating the implosion atomic bomb concept. This work culminated in the Trinity atomic test near Alamogordo on July 16, 1945. This implosion effect demarcated the approach to explosive science and technology the Laboratory has followed ever since, including development of high-explosive synthesis and formulation, small and large test and diagnostic facilities, shock dynamics theory, high-explosive system design engineering, and three-dimensional implosion modeling and simulation using some of the fastest computers in the world. This work also ushered in a period of broader application of precision high explosives in conventional munitions, demolition, mining and oil exploration, and space travel.
The current one-year allocation (w20 qburst) is the first year in a two year allocation of the same name. The project has supported two publications in peer-review journals, another manuscript in preparation for publication, a white paper for the Astro2020 Decadal Survey, and a number of talks (see below). Code development continues on implementing a neutrino quantum kinetic equation solver into BURST, now called QBURST. While implementing coherent and forward-scattering processes into the dynamical neutrino evolution equations, multiple numerical issues have appeared. We have remedied a number of these issues through extensive debugging and testing, which include streamlining interpolation and implementing new ODE integration techniques. Further testing is required to solve the problem at a precision of better than one part in 10 6 . We expect that we will understand the numerical difficulties and implement solutions by end of year 2021.
The overall goal of the Variable Precision Computing project is exploring and identifying ways to reduce internodal communication cost in production physics simulation experiments running on a distributed-memory systems by compressing data, either in a lossy or lossless way, thus resulting in a significant computational performance increase. Among the several approaches proposed, the one discussed here has been proposed, designed and implemented by me. It concerns the application of information theory-derived metrics to classical molecular dynamics and computational fluid dynamics simulation experiments.
The objective of this subcontract was to identify opportunities for the use of mixed precision within iterative solvers and to explore these opportunities both theoretically and experimentally. All quarterly milestones were achieved. We summarize the achievements each quarter in sections below.
In this final technical report, we report on the main products from the scope of the work of the award, in particular the Ph.D. dissertations that summarize the work done by the three graduate students who completed their requirements and defenses during calendar 2021, after completing data analyses on the PREX-II and CREX experiments which made precision measurements of neutron RMS radii of 208 Pb and 48 Ca nuclei.
On April 21–23, the U.S. Department of Energy’s (DOE’s) Advanced Manufacturing Office (AMO) within the office of Energy Efficiency and Renewable Energy (EERE) held the second in a series of workshops on different topics related to semiconductor research and development (R&D) to increase energy efficiency. This workshop focused on ultra-energy-efficient devices and the ultra-precision manufacturing (UPM) processes and next-generation control and metrology technologies needed to manufacture these devices. In addition to the industry needs and RDD&D opportunities, AMO’s new goal on greenhouse gas (GHG) reduction was addressed. The output of this workshop will inform AMO’s future R&D portfolio investments; provide perspectives on trends, drivers, and challenges for ultra-energy-efficient devices and enabling technologies; and help the stakeholder community understand the opportunities on the horizon.
In this contribution to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021) we review recent progress in the evaluation and application of the Energy-Energy Correlator (EEC) event shape observable in $e^+e^⁻$ annihilation, hadronic collisions, and deep inelastic scattering. The importance of EEC as a precision probe of the perturbative and non perturbative aspects of QCD dynamics is emphasized. It can be used to extract the strong coupling constant and to constrain TMD distribution functions. Closely related energy-correlation shape variables have also been used to tag boosted objects produced in high energy collisions. The opportunities to study EEC at the future Electron-Ion Collider are also highlighted.