L. J. Rosenberg
A5036756145- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Astrophysics and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Neutrino Physics Research
- Nuclear reactor physics and engineering
- Computational Physics and Python Applications
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- Cold Atom Physics and Bose-Einstein Condensates
- Nuclear Physics and Applications
- Radio Astronomy Observations and Technology
- Muon and positron interactions and applications
- Galaxies: Formation, Evolution, Phenomena
- Stochastic processes and statistical mechanics
- Statistical Methods and Bayesian Inference
- Astronomy and Astrophysical Research
- Radiation Detection and Scintillator Technologies
- Adaptive optics and wavefront sensing
- Quantum Mechanics and Applications
- Superconducting and THz Device Technology
University of Washington
2015-2024
Seattle University
2006-2024
University of Mary Washington
2024
Massachusetts Institute of Technology
2001-2016
Washington Center
2013
Lawrence Livermore National Laboratory
2000-2007
Indiana University – Purdue University Indianapolis
2006
University of Rochester
2000-2005
Brookhaven National Laboratory
2003-2004
Indiana University
2004
Axions in the micro eV mass range are a plausible cold dark matter candidate and may be detected by their conversion into microwave photons resonant cavity immersed static magnetic field. The first result from such an axion search using superconducting first-stage amplifier (SQUID) is reported. SQUID amplifier, replacing conventional GaAs field-effect transistor successfully reached axion-photon coupling sensitivity band set present models sets stage for definitive utilizing near...
This Letter reports on a cavity haloscope search for dark matter axions in the Galactic halo mass range 2.81-3.31 μeV. utilizes combination of low-noise Josephson parametric amplifier and large-cavity to achieve unprecedented sensitivity across this range. excludes full axion-photon coupling values predicted benchmark models invisible axion that solve strong CP problem quantum chromodynamics.
Pseudorapidity distributions of charged particles emitted in $Au+Au$, $Cu+Cu$, $d+Au$, and $p+p$ collisions over a wide energy range have been measured using the PHOBOS detector at RHIC. The centrality dependence both particle multiplicity midrapidity were measured. with $|\eta|<5.4$, which account for between 95% 99% total charged-particle emission associated collision participants, are presented different centralities. Both density, $dN_{ch}/d\eta$, multiplicity, $N_{ch}$, found to...
We present measurements of the pseudorapidity distribution primary charged particles produced in $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at three energies, $\sqrt{{s}_{NN}}=19.6$, 130, and 200 GeV, for a range collision centralities. The narrows more central excess are high peripheral collisions. For given centrality, however, distributions found to scale with energy according ``limiting fragmentation'' hypothesis. universal fragmentation region described by this scaling grows...
We present the first measurement of pseudorapidity densities primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For most central collisions, we find charged-particle density to be dN/deta|(|eta|<1) 408+/-12(stat)+/-30(syst) GeV 555+/-12(stat)+/-35(syst) GeV, values that are higher than any previously observed nuclear collisions. Compared proton-antiproton our data show an increase per participant by more 40% energy.
Recent determinations of cosmological parameters point to a flat Universe, whose total energy density is composed about two-thirds vacuum and one-third matter. Ordinary baryonic matter relegated small fraction the latter, within which luminous part an order magnitude smaller yet. Particle dark matter, i.e., one or more relic particle species from big bang, thus strongly suggested as dominant component in Universe. The axion, hypothetical elementary pseudoscalar arising Peccei-Quinn solution...
This Rapid Communication describes the measurement of elliptic flow for charged particles in Au+Au collisions at $\sqrt{{s}_{\mathit{NN}}}=200$ GeV using PHOBOS detector Relativistic Heavy Ion Collider. The measured azimuthal anisotropy is presented over a wide range pseudorapidity three broad collision centrality classes first time this energy. Two distinct methods extracting signal were used to reduce systematic uncertainties. falls sharply with increasing $|\ensuremath{\eta}|$ 200 all...
We have built and operated a large-scale axion detector, based on method originally proposed by Sikivie, to search for halo axions. The apparatus consists of cylindrical tunable high-Q microwave cavity threaded axially static high magnetic field. This field stimulates axions that enter the convert into single photons. conversion is resonantly enhanced when resonant frequency near rest mass energy. experiment cooled 1.5 K electromagnetic power spectrum emitted measured an ultra-low-noise...
The axion is a hypothetical elementary particle and cold dark matter candidate. In this rf cavity experiment, halo axions entering resonant immersed in static magnetic field convert into microwave photons, with the resulting photons detected by low-noise receiver. ADMX Collaboration presents new limits on axion-to-photon coupling local mass density from search range $1.9--2.3\ensuremath{\mu}\mathrm{eV},$ broadening to $1.9--3.3\ensuremath{\mu}\mathrm{eV}.$ addition, we report first results...
We have performed a high resolution search for galactic halo axions in cold flows using microwave cavity detector. The analysis procedure and other details of this are described. No axion signal was found the mass range $1.98--2.17\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$. place upper limits on density local discrete based result.
From a sample of hadronic events produced in ${e}^{+}{e}^{\ensuremath{-}}$ collisions, semileptonic decays heavy particles have been isolated and used to obtain measurement for the bottom-quark lifetime [1.8\ifmmode\pm\else\textpm\fi{}0.6 (stat.)\ifmmode\pm\else\textpm\fi{}0.4(syst.)]\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}12}$ sec.
The μeV axion is a well-motivated extension to the standard model. Axion Dark Matter eXperiment (ADMX) collaboration seeks discover this particle by looking for resonant conversion of dark-matter axions microwave photons in strong magnetic field. In Letter, we report results from pathfinder experiment, ADMX "Sidecar," which designed pave way future, higher mass, searches. This testbed experiment lives inside and operates tandem with main experiment. Sidecar excludes masses three widely...
The most sensitive direct method to establish the absolute neutrino mass is observation of endpoint tritium beta-decay spectrum. Cyclotron radiation emission spectroscopy (CRES) a precision spectrographic technique that can probe much unexplored range with resolution. A lower bound set by observations oscillations, while KATRIN experiment—the current-generation experiment based on magnetic adiabatic collimation an electrostatic (MAC-E) filter—will achieve sensitivity . CRES aims avoid...
It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting magnetic field never observed directly. We demonstrate single-electron detection novel radio-frequency spectrometer. The relativistic shift the frequency permits precise energy measurement. Precise beta spectroscopy gaseous sources is key technique modern efforts to measure neutrino mass via tritium decay end...
Searching for axion dark matter, the ADMX Collaboration acquired data from January to October 2018, over mass range 2.81–3.31 μeV, corresponding frequency 680–790 MHz. Using an haloscope consisting of a microwave cavity in strong magnetic field, experiment excluded Dine-Fischler-Srednicki-Zhitnisky (DFSZ) axions at 90% confidence level and 100% matter density this entire range, except few gaps due mode crossings. This paper explains full analysis run 1B, motivating choices informed by...
We describe the first implementation of a Josephson Traveling Wave Parametric Amplifier (JTWPA) in an axion dark matter search. The operation JTWPA for period about two weeks achieved sensitivity to axion-like particle with axion-photon couplings above 10-13 Ge V-1 over narrow range masses centered around 19.84 µeV by tuning resonant frequency cavity 4796.7-4799.5 MHz. was operated insert experiment as part independent receiver chain that attached 0.56-l cavity. ability deliver high gain...
We report the first results of a high-sensitivity $(\ensuremath{\sim}{10}^{\ensuremath{-}23}\mathrm{W})$ search for light halo axions through their conversion to microwave photons. At 90% confidence level, we exclude Kim-Shifman-Vainshtein-Zakharov axion mass $2.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ $3.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}\mathrm{eV}$ as dark matter in our galaxy.
The charged-particle pseudorapidity density dNch/dη has been measured for Au+Au collisions at √sNN=130GeV RHIC, using the PHOBOS apparatus. total number of charged particles produced 3% most-central |η|≤5.4 is found to be 4200±470. evolution with centrality discussed, and compared model calculations data from proton-induced collisions. show an enhancement in production midrapidity, while fragmentation regions, results are consistent expectations pp pA scattering.Received 6 June...
The PHOBOS experiment has measured the charged particle multiplicity at mid-rapidity in Au+Au collisions sqrt(s_NN) = 200 GeV as a function of collision centrality. Results on dN/deta(eta<1) divided by number participating nucleon pairs, , are presented . As was found from similar data 130 GeV, can be equally well described parton saturation models and two-component fits which include contributions that scale Npart binary collisions, Ncoll. We compare two energies means ratio R(200/130)...
We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt(s_NN) = 200 GeV. The spectra were measured for momenta p_T from 0.25 to 4.5 GeV/c a rapidity range 0.2 < y_pi 1.4. evolution the is studied as function collision centrality, 65 344 participating nucleons. results are compared data proton-antiproton and lower RHIC energies. find significant change spectral shape between peripheral collisions. Comparing central collisions, we that yields...
Exclusive ${\ensuremath{\pi}}^{\ensuremath{-}}$ and charged-particle production in collisions of Ar+KCl is studied at incident energies from 0.4 to 1.8 GeV/u. Complete disintegration both nuclei observed. The correlation between total charge multiplicity shows no islands anomalous pion production. For constant numbers proton participants the distributions are Poissons. central $〈{n}_{{\ensuremath{\pi}}^{\ensuremath{-}}}〉$ increases smoothly first order linearly with c.m. energy. Disagreement...
▪ Abstract The axion, a favored dark matter candidate, is expected to have very small mass and extraordinarily weak couplings. Although it has eluded discovery or exclusion for three decades, remains the most compelling solution strong-CP problem. Axions may be detected by their resonant conversion RF photons in microwave cavity permeated magnetic field. Experiments already set significant limits on axion's photon coupling; progress detection schemes at below standard quantum limit will soon...