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At least 235 records · Page 13

A Beamdump facility at Jefferson Lab

The potential of the intense secondary muon, neutrino, and (hypothetical) light dark matter beams at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) is explored. These are produced in the high-power dumps with high-current electron beams. Light dark matter searches with the approved Beam Dump eXperiment (BDX) are driving the realization of a new underground vault behind Hall A that could be extended to a Beamdump Facility with little additional installations. High-energy muons created via the Bethe–Heitler process uniquely do not proceed through the more common pion production and decay channels. Several possible muon physics applications are highlighted. Neutrino detector technologies and experiments suitable for a beamdump facility are outlined.

Accelerator Physics↗

Luminosity determination using Z boson production at the CMS experiment

The measurement of Z boson production is presented as a method to determine the integrated luminosity of CMS data sets. The analysis uses proton–proton collision data, recorded by the CMS experiment at the CERN LHC in 2017 at a center-of-mass energy of 13 TeV. Events with Z bosons decaying into a pair of muons are selected. The total number of Z bosons produced in a fiducial volume is determined, together with the identification efficiencies and correlations from the same data set, in small intervals of 20 pb –1 of integrated luminosity, thus facilitating the efficiency and rate measurement as a function of time and instantaneous luminosity. Using the ratio of the efficiency-corrected numbers of Z bosons, the precisely measured integrated luminosity of one data set is used to determine the luminosity of another. For the first time, a full quantitative uncertainty analysis of the use of Z bosons for the integrated luminosity measurement is performed. The uncertainty in the extrapolation between two data sets, recorded in 2017 at low and high instantaneous luminosity, is less than 0.5%. We show that the Z boson rate measurement constitutes a precise method, complementary to traditional methods, with the potential to improve the measurement of the integrated luminosity.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Measurement of groomed event shape observables in deep-inelastic electron-proton scattering at HERA

The H1 Collaboration at HERA reports the first measurement of groomed event shape observables in deep inelastic electron-proton scattering (DIS) at $\sqrt{s} =319$ GeV, using data recorded between the years 2003 and 2007 with an integrated luminosity of 351 pb -1 . Event shapes provide incisive probes of perturbative and non-perturbative QCD. Grooming techniques have been used for jet measurements in hadronic collisions; this paper presents the first application of grooming to DIS data. The analysis is carried out in the Breit frame, utilizing the novel Centauro jet clustering algorithm that is designed for DIS event topologies. Events are required to have squared momentum-transfer $Q^2 > 150$ GeV 2 and inelasticity $0.2< y < 0.7$. We report measurements of the production cross section of groomed event 1-jettiness and groomed invariant mass for several choices of grooming parameter. Monte Carlo model calculations and analytic calculations based on Soft Collinear Effective Theory are compared to the measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Search for hadronic decays of feebly-interacting particles at NA62

The NA62 experiment at CERN has the capability to collect data in a beam-dump mode, where 400 GeV protons are dumped on an absorber. In this configuration, New Physics particles, including dark photons, dark scalars, and axion-like particles, may be produced in the absorber and decay in the instrumented volume beginning approximately 80 m downstream of the dump. A search for these particles decaying in flight to hadronic final states is reported, based on an analysis of a sample of 1.4 x 10 17 protons on dump collected in 2021. No evidence of a New Physics signal is observed, excluding new regions of parameter spaces of multiple models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Screening of the Protective Actions under the Laser Irradiation of Bio-Objects: Experimental Results and Physical Model

The screening of protective radiations that occur during laser radiation of biological tissues have been experimentally studied. The metallic and dielectric screens with different shape have been used for screening. The physical model of generation of the secondary radiation that generates the protective effects, which lead to a substantial increase in the environmental resistance of living organisms placed nearby, has been suggested. It has been assumed that this radiation is mainly concentrated in the frequency range lower than 10 GHz.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

MCML: Combining physical constraints with experimental data for a multi-purpose meta-generalized gradient approximation

The predictive power of density functional theory for materials properties can be improved without increasing the overall computational complexity by extending the generalized gradient approximation (GGA) for electronic exchange and correlation to density functionals depending on the electronic kinetic energy density in addition to the charge density and its gradient, resulting in a meta-GGA. Here, we propose an empirical meta-GGA model that is based both on physical constraints and on experimental and quantum chemistry reference data. Overall, the resulting optimized meta-GGA MCML yields improved surface and gas phase reaction energetics without sacrificing the accuracy of bulk property predictions of existing meta-GGA approaches.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Integrated (Physical and Digital) Collaborative Experimentation: Advancing Dialog and Leveraging by Aerospace Researchers and Developers

This paper 1) documents findings and observations from the American Institute of Aeronautics and Astronautics (AIAA) Ground Test Technical Committee (GTTC) Future of Ground Test Working Group and the Applied Aeronautics Technical Committee (APATC) Collaborative Experiments & Computation Discussion Group, and 2) develops a more focused approach for sharing and advancing integrated development and use of physical experimental and computational capabilities for aerospace research and development. The GTTC and APATC are engaging with the larger AIAA technical community by creating a Focus Group on this topical area that will support working together on common interests in the public domain. This paper summarizes the knowledge capture from the last ten+ years and proposes a structure and scope going forward for the new, combined Focus Group.

ground testing↗

An Experimental and Theoretical High Energy Physics Program

The Purdue High Energy Physics Group conducts research in experimental and theoretical elementary particle physics and experimental high energy astrophysics. Our goals, which we share with high energy physics colleagues around the world, are to understand at the most fundamental level the nature of matter, energy, space and time, and in order to explain the birth, evolution and fate of the Universe. The experiments in which we are currently involved are: CDF, CLEO-c, CMS, LSST, and VERITAS. We have been instrumental in establishing two major in-house facilities: The Purdue Particle Physics Microstructure Detector Facility (P3MD) in 1995 and the CMS Tier-2 center in 2005. The research efforts of the theory group span phenomenological and theoretical aspects of the Standard Model as well as many of its possible extensions. Recent work includes phenomenological consequences of supersymmetric models, string theory and applications of gauge/gravity duality, the cosmological implications of massive gravitons, and the physics of extra dimensions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Direct observation of the dead-cone effect in quantum chromodynamics

In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower, which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass m Q and energy E, within a cone of angular size m Q /E around the emitter. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Probing QCD and hadron physics: highlights of experimental results

The rich set of data collected from HERA, Tevatron and LHC collisions offer an extraordinary possibility to test different aspects of perturbative Quantum Chromodynamics. A selection of recent results illustrates the variety and precision of these tests. The comparison of the experimental data with the most recent theoretical predictions demonstrates the advances made in the theoretical field.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Physical model and experimental validation of a high temperature proton exchange membrane electrochemical hydrogen pump cell for efficient single-stage extraction of low concentration hydrogen gas

There is interest in valorization of existing natural gas infrastructure to facilitate the co-transportation of hydrogen via blending of hydrogen gas initially at limited concentrations of 1–20 vol% H2 and to subsequently extract hydrogen at fuel cell quality standards (SAE J2719/ISO14687-2). High temperature proton exchange membrane electrochemical hydrogen pump (HT-PEM EHP) based on phosphoric acid doped polybenzimidazole (PA-PBI) exhibits good performance at elevated temperatures (>120 °C), which provides desirable tolerance to non-methane natural gas constituents that are problematic for lower temperature based EHP. To better understand the suitability of the HT-PEM EHP for such gas separation processes, a two-dimensional model of EHP based on PA-PBI was developed. The model is validated for several relevant operating conditions and across cells with differing amounts of phosphoric acid content in the electrodes. Operando micro x-ray computed tomography (CT) imaging of an HT-PEM EHP was used to further validate physical parameters and assumptions of the model. The impacts of pressure, relative humidity of the anode feed, and concentration of feed gases on separation performance are investigated. This study shows that a specific energy of separation of 5.1 kWh/kg H2 at a hydrogen recovery factor (HRF) of 50 vol% can be achieved in a single stage with the EHP, producing fuel cell quality hydrogen purity of 99.99 vol% H2 from a 2 vol% H2/CH4 feed blend, while pressurizing the product H2 at a pressure ratio of 1.3 relative to feed pressure.

Stansberry, John M↗

Closeout Report: Experimental High Energy Physics Group at the University of South Alabama

The High Energy Physics group at the University of South Alabama has been supported by this research grant (DE-FG02-96ER40970) since 1996. One researcher, Dr. Merrill Jenkins, has been supported on this grant during this time worked on fixed target experiments at the Fermi National Accelerator Laboratory, west of Chicago, Illinois. These experiments have been E-705, E-771, E-871 (HyperCP) and E-921 (CKM) before it was canceled for budgetary reasons. After the cancellation of CKM, Dr. Jenkins joined the Compact Muon Solenoid (CMS) experiment as an associate member via the High Energy Physics Group at the Florida State University. A second, recently tenured faculty member, Dr. Romulus Godang joined the group in 2009 and has been supported by this grant since then. Dr. Godang is working on the BaBaR experiment at SLAC and has joined the Belle-II experiment located in Japan at KEK. According to the instructions sent to us by our grant monitor, we are to concentrate on the activities over the last three years in this closeout report.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Research in Particle Theory and Experiment at the University of Cincinnati (Final Technical Report)

Task A - Theory: Research in theoretical physics in the Department of Physics at the University of Cincinnati has been funded by the U.S. Department of Energy starting in 1984. Professors Peter Suranyi, Louis Witten, Fred Mansouri, L.C.R. Wijewardhana, Alexander Kagan and Philip Argyres have served as P.I.'s of the Cincinnati DOE theory task. Task B - Heavy Flavor: Physics Research in experimental particle physics in the Department of Physics at the University of Cincinnati has been funded by the U.S. Department of Energy since 1999. Professor Kay Kinoshita has served as P.I. on Task B since its inception. Task C - Neutrinos: Over the past three years, Task C has been measuring the properties of neutrinos with the MiniBooNE and Daya Bay detectors and building two new neutrino experiments: MicroBooNE and LArIAT. In addition, the PI (Randy Johnson) has joined the long leadtime experiment, LBNE, and has participated in the R&D report for CHiPs. Results and progress on each of these experiments will be summarized below.

Wijewardhana, L. C. Rohana↗

Report on Research in Experimental High Energy Physics

In the past three years the groups supported by the DOE have all made significant progress and posted major successes. The Minnesota CMS group has played leading roles in five data analyses and has had major roles in detector operations, the data management and the detector upgrades that are planned for for the LHC and those that are planned for the high-luminosity LHC. The CDMS-II experiment held the lead in WIMP sensitivity over the last decade, and is still the most sensitive detector in the world in the low WIMP mass region, with a recent 3σ hint of 8 GeV/c 2 WIMP candidates in the silicon data. SuperCDMS, with three orders of magnitude better electron recoil background rejection, has been collecting data since October 2011. Since all dark matter experiments require a better understanding of neutron backgrounds to make further advances in sensitivity, Cushman has expanded the Minnesota effort on backgrounds to the national level, where she is leading a coordinated effort in neutron simulations for underground physics. The work of Mandic on 100 mm detectors both for Super-CDMS and beyond has advanced rapidly. Also at the Intensity Frontier, the BESIII experiment has had a successful year of operation largely focused on searches for and studies of new "charmonium-like" states above DD threshold. At least one new state has been observed so far, with hints of others. An intensive effort to understand their nature and gain new insight into the strong interaction continues. BESIII has also produced a large number of other results in charmonium decay and light-hadronic physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Experimental High Energy Physics Research

This final report summarizes activities of the Florida Tech High Energy Physics group supported by DOE under grant #DE-SC0008024 during the period June 2012 – March 2015. We focused on one of the main HEP research thrusts at the Energy Frontier by participating in the CMS experiment. We were exploiting the tremendous physics opportunities at the Large Hadron Collider (LHC) and prepared for physics at its planned extension, the High-Luminosity LHC. The effort comprised a physics component with analysis of data from the first LHC run and contributions to the CMS Phase-2 upgrades in the muon endcap system (EMU) for the High-Luminosity LHC. The emphasis of our hardware work was the development of large-area Gas Electron Multipliers (GEMs) for the CMS forward muon upgrade. We built a production and testing site for such detectors at Florida Tech to complement future chamber production at CERN. The first full-scale CMS GE1/1 chamber prototype ever built outside of CERN was constructed at Florida Tech in summer 2013. We conducted two beam tests with GEM prototype chambers at CERN in 2012 and at FNAL in 2013 and reported the results at conferences and in publications. Principal Investigator Hohlmann served as chair of the collaboration board of the CMS GEM collaboration and as co-coordinator of the GEM detector working group. He edited and authored sections of the detector chapter of the Technical Design Report (TDR) for the GEM muon upgrade, which was approved by the LHCC and the CERN Research Board in 2015. During the course of the TDR approval process, the GEM project was also established as an official subsystem of the muon system by the CMS muon institution board. On the physics side, graduate student Kalakhety performed a Z' search in the dimuon channel with the 2011 and 2012 CMS datasets that utilized 20.6 fb⁻¹ of p-p collisions at √s = 8 TeV. For the dimuon channel alone, the 95% CL lower limits obtained on the mass of a Z' resonance are 2770 GeV for a Z' with the same standard-model couplings as the Z boson. Our student team operated a Tier-3 cluster on the Open Science Grid (OSG) to support local CMS physics analysis and remote OSG activity. As a service to the HEP community, Hohlmann participated in the Snowmass effort over the course of 2013. Specifically, he acted as a liaison for gaseous detectors between the Instrumentation Frontier and the Energy Frontier and contributed to five papers and reports submitted to the summer study.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗