M. Heffner
A5009831425- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Astrophysics and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- X-ray Spectroscopy and Fluorescence Analysis
- Atomic and Molecular Physics
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Nuclear Materials and Properties
- Electron and X-Ray Spectroscopy Techniques
- Magnetic confinement fusion research
- Radioactivity and Radon Measurements
- Fusion materials and technologies
- Quantum, superfluid, helium dynamics
- Radiation Therapy and Dosimetry
- Statistical Methods and Bayesian Inference
Lawrence Livermore National Laboratory
2015-2024
University of Alabama
2023
Stony Brook University
2005-2020
New Mexico State University
2013-2019
University of Massachusetts Amherst
2019
Abilene Christian University
2003-2018
Banaras Hindu University
2003-2018
Augustana University
2014-2018
Charles University
2018
Brookhaven National Laboratory
2005-2018
This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements 644 papers, we list, evaluate, and average measured properties gauge bosons, leptons, quarks, mesons, baryons. We summarize searches for hypothetical particles such as Higgs heavy neutrinos, supersymmetric particles. All the search limits are listed in Summary Tables. also give numerous tables, figures, formulae, reviews topics Standard Model, detectors, probability,...
We report first results on elliptic flow of identified particles at midrapidity in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathrm{NN}}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}130\mathrm{GeV}$ using the STAR TPC RHIC. The as a function transverse momentum and centrality differs significantly for different masses. This dependence can be accounted hydrodynamic models, indicating that system created shows behavior consistent with collective hydrodynamical flow. fit to data...
Two-pion correlation functions in Au+Au collisions at $\sqrt{s_{NN}} = 130$ GeV have been measured by the STAR (Solenoidal Tracker RHIC) detector. The source size extracted fitting correlations grows with event multiplicity and decreases transverse momentum. Anomalously large sizes or emission durations, which suggested as signals of quark-gluon plasma formation rehadronization, are not observed. HBT parameters display a weak energy dependence over broad range $\sqrt{s_{NN}}$.
We have measured the proton elliptic flow excitation function for Au+Au system spanning beam energy range (2–8)AGeV. The shows a transition from negative to positive at energy, Etr∼4AGeV. Detailed comparisons with calculations relativistic Boltzmann equation are presented. suggest softening of nuclear state stiff form ( K∼380MeV) low energies Ebeam≤2AGeV) softer K∼210MeV) higher Ebeam≥4AGeV) where calculated baryon density ρ∼4ρ0.Received 21 September...
The next-generation Enriched Xenon Observatory (nEXO) is a proposed experiment to search for neutrinoless double beta ($0\nu\beta\beta$) decay in $^{136}$Xe with target half-life sensitivity of approximately $10^{28}$ years using $5\times10^3$ kg isotopically enriched liquid-xenon time projection chamber. This improvement two orders magnitude over current limits obtained by significant increase the mass, monolithic and homogeneous configuration active medium, multi-parameter measurements...
Abstract The nEXO neutrinoless double beta (0 νββ ) decay experiment is designed to use a time projection chamber and 5000 kg of isotopically enriched liquid xenon search for the in 136 Xe. Progress detector design, paired with higher fidelity its simulation an advanced data analysis, based on one used final results EXO-200, produce sensitivity prediction that exceeds half-life 10 28 years. Specifically, improvements have been made understanding production scintillation photons charge as...
The minimum-bias multiplicity distribution and the transverse momentum pseudorapidity distributions for central collisions have been measured negative hadrons ( h(-)) in Au+Au interactions at square root of ([s(NN)]) = 130 GeV. density midrapidity 5% most is dN(h(-))/d(eta)/(eta 0) 280+/-1(stat)+/-20(syst), an increase per participant 38% relative to pp same energy. mean 0.508+/-0.012 GeV/c larger than Pb+Pb lower energies. scaling h(-) yield a strong function p( perpendicular). almost...
Momentum spectra of charged pions over nearly full rapidity coverage from target to beam have been extracted $0\ensuremath{-}5%$ most central $\text{Au}+\text{Au}$ collisions in the energy range $2A$ $8A\phantom{\rule{0.3em}{0ex}}\text{GeV}$ by E895 experiment. Using a thermal parametrization fit transverse mass spectra, density distributions are extracted. The observed compared with predictions RQMD version 2.3 cascade model and also including longitudinal flow. total $4\ensuremath{\pi}$...
We report results on the ratio of midrapidity antiproton-to-proton yields in Au+Au collisions at sqrt[s(NN)] = 130 GeV per nucleon pair as measured by STAR experiment RHIC. Within rapidity and transverse momentum range /y/<0.5 0.4<p(t)<1.0 GeV/c, is essentially independent either or rapidity, with an average 0.65+/-0.01((stat))+/-0.07((syst)) for minimum bias collisions. errors, no strong centrality dependence observed. The indicate that this RHIC energy, although p-p production becomes...
Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements collective sideward flow in Au+Au collisions beam energies 2A, 4A, 6A, and 8A GeV are presented form in-plane transverse momentum <p(x)> first Fourier coefficient azimuthal anisotropy v(1). These indicate a smooth variation as function energy. The data compared with four nuclear transport models which have an orientation towards this energy range. All exhibit some qualitative trends similar to...
Rapidity distributions of protons from central ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ collisions measured by the E895 Collaboration in energy range $(2--8)A\mathrm{GeV}$ at Brookhaven AGS are presented. Longitudinal flow parameters derived using a thermal model including collective longitudinal expansion extracted these distributions. The results show an approximately linear increase velocity, $〈\ensuremath{\beta}\ensuremath{\gamma}{〉}_{L}$, as function logarithm beam energy.
We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions square root s(NN) = 130 GeV by STAR experiment RHIC. The transverse mass distributions measured momentum range 0.25<p( perpendicular)<0.95 GeV/c are found to fall less steeply for more central collisions. extrapolated rapidity density is scale approximately with negative hadron multiplicity density.
We present the first measurement of midrapidity vector meson φ production in Au+Au collisions at RHIC (√sNN=130GeV) from STAR detector. For 11% highest multiplicity collisions, slope parameter an exponential fit to transverse mass distribution is T=379±50(stat)±45(syst)MeV, yield dN/dy=5.73±0.37(stat)±0.69(syst) per event, and ratio Nφ/Nh− found be 0.021±0.001(stat)±0.004(syst). The measured T for do not change selected bins.Received 17 August...
The first measurements of light antinucleus production in Au+Au collisions at the Relativistic Heavy-Ion Collider are reported. observed rates for d macro and (3)He much larger than lower energy nucleus-nucleus collisions. A coalescence model analysis yields indicates that there is little or no increase antinucleon freeze-out volume compared to CERN SPS energy. These analyses also indicate smaller volume.
Purpose The purpose of this research is to present a guiding integrative framework for knowledge management that encompasses fusion process creating new and technological innovations, as well propose method applying the in managerial decision making process. Design/methodology/approach integrates multiple perspectives formation innovation from both researchers practitioners. framework, which authors label process, presented an organizational learning cycle, sub‐processes acquisition...
Progress on a method of barium tagging for the nEXO double beta decay experiment is reported. Absorption and emission spectra deposits atoms ions in solid xenon matrices are presented. Excitation prominent lines, temperature dependence, bleaching fluorescence reveal existence different matrix sites. A regular series sharp lines observed ${\mathrm{Ba}}^{+}$ identified with some type hydride molecule. Lower limits quantum efficiency principal Ba transition Under current conditions, an image...
Future tonne-scale liquefied noble gas detectors depend on efficient light detection in the VUV range. In past years Silicon Photomultipliers (SiPMs) have emerged as a valid alternative to standard photomultiplier tubes or large area avalanche photodiodes. The next generation double beta decay experiment, nEXO, with 5 tonne liquid xenon time projection chamber, will use SiPMs for detecting $178\,\text{nm}$ scintillation light, order achieve an energy resolution of $\sigma / Q_{\beta\beta} =...
Large detectors employing xenon are a leading technology in existing and planned searches for new physics, including neutrinoless double beta decay ($0\nu\beta\beta$) dark matter. While upcoming will employ target masses of ton or more, further extending gas liquid phase Xe to the kton scale would enable extremely sensitive next-generation rare phenomena. The key challenge this well beyond is acquisition itself. We describe motivation time projection chambers (TPCs) possible avenues that...
We present the first excitation function of pi(-) intensity interferometry at Alternating Gradient Synchrotron (AGS) energies (2-8 A GeV). The sensitivity multidimensional correlation functions to geometry and dynamics pion-emitting system provides a stringent test transport models heavy ion collisions. Detailed comparisons with realistic model, both without an explicit nuclear mean field, suggest that beam energy evolution in reaction is different model than data. significantly increased...
The yield for the multistrange Xi(-) hyperon has been measured in 6A GeV Au+Au collisions via reconstruction of its decay products pi(-) and Lambda, latter also being reconstructed from daughter tracks p. measurement is rather close to threshold production therefore provides an important test model predictions. Lambda are compared several centralities. In central found be excellent agreement with statistical transport predictions, suggesting that hadron approaches chemical equilibrium high...