Gail Hanson
A5029265065- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Neutrino Physics Research
- Cosmology and Gravitation Theories
- Muon and positron interactions and applications
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Medical Imaging Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Radiation Detection and Scintillator Technologies
- Superconducting Materials and Applications
- Nuclear physics research studies
- Distributed and Parallel Computing Systems
- Black Holes and Theoretical Physics
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- International Science and Diplomacy
- Nuclear reactor physics and engineering
- CCD and CMOS Imaging Sensors
- Quantum Mechanics and Applications
University of California, Riverside
2016-2025
University of California System
2024-2025
A. Alikhanyan National Laboratory
2022-2024
Institute of High Energy Physics
2017-2024
University of Antwerp
2024
University of California, San Diego
2023
Stanford University
1984-2018
Vrije Universiteit Brussel
2017
Brookhaven National Laboratory
2015
European Organization for Nuclear Research
2014
We present evidence, from a study of multihadronic final states produced in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at center-of-mass energies between 3.90 and 4.60 GeV, for the production new neutral state with mass 1865\ifmmode\pm\else\textpm\fi{}15 MeV/${\mathit{c}}^{2}$ decay width less than 40 that decays to ${K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$...
We have observed a second sharp peak in the cross section for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons}$ at center-of-mass energy of 3.695\ifmmode\pm\else\textpm\fi{}0.004 GeV. The upper limit full width half-maximum is 2.7 MeV.
We have found evidence for jet structure in ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons}$ at center-of-mass energies of 6.2 and 7.4 GeV. At GeV the jet-axis angular distribution integrated over azimuthal angle was determined to be proportional $1+(0.78\ifmmode\pm\else\textpm\fi{}0.12){cos}^{2}\ensuremath{\theta}$.
We report evidence for the production of a new narrow charged state in e+e− annihilation at center-of-mass energy 4.03 GeV. This state, which has mass 1876± 15 MeV/c2, is observed exotic channel K∓π±π±, but not nonexotic K∓π+π−. It produced primarily association with system 2.01±0.02 GeV/c2. These characteristics are just those expected charmed meson.Received 21 July 1976DOI:https://doi.org/10.1103/PhysRevLett.37.569©1976 American Physical Society
We present a study of the decay properties charmed D mesons produced near peak ψ''(3770) resonance in e+e− annihilation. Branching fractions for nine Cabibbo-favored and three Cabibbo-suppressed modes are presented along with upper limits on one additional four modes. A Kππ-decay-mode Dalitz plots reveals large quasi-two-body pseudoscalar-vector component D0 decays an apparent nonuniform population plot D+ into K−π+π+. Using tagged events, we measure charged-particle multiplicity...
The average lifetime of bottom hadrons was measured with the Mark II vertex detector at storage ring PEP. determined by measuring impact parameters leptons produced in decays. ${\ensuremath{\tau}}_{b}=({12.0}_{\ensuremath{-}3.6}^{+4.5}\ifmmode\pm\else\textpm\fi{}3.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}$ sec found.
We have measured the total cross section for electron-positron annihilation into three or more hadrons, with at least two charged particles in final state. The measurement was made a center-of-mass energy of 4 GeV $2\ensuremath{\pi}\ensuremath{-}\mathrm{s}\mathrm{r}$ nonmagnetic detector. With 88 events detected, we obtain model-independent lower limit on hadron production 9.6 \ifmmode\pm\else\textpm\fi{} 1.4 nb; calculation detection efficiency based invariant phase-space pions leads to 26...
We describe the status of our effort to realize a first neutrino factory and progress made in understanding problems associated with collection cooling muons towards that end. summarize physics can be done factories as well intense cold beams muons. The potential muon colliders is reviewed, both Higgs Factories compact high energy lepton colliders. timescale research development reviewed latest designs channels including promise ring coolers achieving longitudinal transverse simultaneously....
We present a new high-statistics measurement of the cross section for process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ at center-of-mass energy 29 GeV invariant pion-pair masses $M({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$ between 350 MeV/${\mathit{c}}^{2}$ and 1.6 GeV/${\mathit{c}}^{2}$. observe ${f}_{2}(1270)$ measure its radiative width to be...
We have measured the mass of Z boson to be 91.14±0.12 GeV/c2, and its width 2.42+0.45−0.35 GeV. If we constrain visible standard-model value, find partial invisible decay modes 0.46±0.10 GeV, corresponding 2.8±0.6 neutrino species, with a 95%-confidence-level upper limit 3.9.Received 12 October 1989DOI:https://doi.org/10.1103/PhysRevLett.63.2173©1989 American Physical Society
We have measured the mass of Z boson to be 91.11±0.23 GeV/c2, and its width 1.61+0.60−0.43 GeV. If we constrain visible standard-model value, find partial invisible decay modes 0.62±0.23 GeV, corresponding 3.8±1.4 neutrino species.Received 24 July 1989DOI:https://doi.org/10.1103/PhysRevLett.63.724©1989 American Physical Society
Measurements of $\ensuremath{\psi}(3097)$ and ${\ensuremath{\psi}}^{\ensuremath{'}}(3686)$ branching fractions for selected hadronic decays are presented. The ratio ${\ensuremath{\psi}}^{\ensuremath{'}}$ to $\ensuremath{\psi}$ these is consistent with the lepton pairs, exception $p\ensuremath{\pi}$ ${K}^{*}K$ which this substantially smaller.
A peak in the $p{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ and $\overline{p}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ invariant-mass spectra at 2.285\ifmmode\pm\else\textpm\fi{}0.006 GeV/${\mathit{c}}^{2}$ is observed, which associated with lowest-lying charmed baryon (${\ensuremath{\Lambda}}_{c}$). cross section times branching ratio of 0.037\ifmmode\pm\else\textpm\fi{}0.012 nb ${E}_{\mathrm{c}.\mathrm{m}.}=5.2$ GeV measured a substantial fraction events produced an equal recoiling mass....
We have observed the decay ${{D}^{*}}^{+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$ and measured its $Q$ value to be 5.7\ifmmode\pm\else\textpm\fi{}0.5 MeV. The width of ${{D}^{*}}^{+}$ is less than 2.0 MeV/${\mathit{c}}^{2}$. observation ${{D}^{*}}^{+}\ensuremath{\rightarrow}({K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}){\ensuremath{\pi}}^{+}$ but not ${{D}^{*}}^{+}\ensuremath{\rightarrow}({K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}){\ensuremath{\pi}}^{+}$ sets an upper limit on...
Measurements of multihadron production in e+e− annihilation at center-of-mass energies between 2.6 and 7.8 GeV are presented. Aside from the narrow resonances ψ(3095) ψ(3684), total hadronic cross section is found to be approximately 2.7 times for muon pairs c.m. below 3.7 4.3 muon-pair above 5.5 GeV. Complicated structure intermediate energies. Charged-particle multiplicities inclusive momentum distributions presented.Received 12 April 1982DOI:https://doi.org/10.1103/PhysRevD.26.969©1982...
The reactions ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ and ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ have been measured at center-of-mass energies 3.0, 3.8, 4.8 GeV production angles of $50\ifmmode^\circ\else\textdegree\fi{}<\ensuremath{\theta}<130\ifmmode^\circ\else\textdegree\fi{}$ over all azimuthal angles. Agreement with quantum electrodynamics is excellent. New limits for...
We present measurements of inclusive anomalous muon production in e+e− annihilations three energy ranges. In all ranges we observe a large rate two-prong events which is compatible with the expected decays pairs heavy leptons. highest range there also appreciable multiprong which, due to its magnitude and momentum dependence, must come part from source other than lepton.Received 8 November 1976DOI:https://doi.org/10.1103/PhysRevLett.38.117©1977 American Physical Society
Events of the type ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\eta}}^{\ensuremath{'}}(958)$ have been observed with Mark II detector at SPEAR by detecting decay mode ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}\ensuremath{\gamma}$. From cross section and known branching fractions ${\ensuremath{\eta}}^{\ensuremath{'}}$ is...
We have observed an azimuthal asymmetry in inclusive hadron production by e+e− annihilation at the center-of-mass energy s=7.4 GeV. The is caused polarization of circulating beams storage ring and allows separate determination transverse longitudinal structure functions. find that dominates for x>0.2 where x scaling variable 2ps.Received 18 August 1975DOI:https://doi.org/10.1103/PhysRevLett.35.1320©1975 American Physical Society
The production of the charmed meson state ${D}^{*+}$ has been observed in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at 29 GeV. fragmentation function for quarks appears to be peaked about $z=0.5$.