M. Sivertz
A5073337135- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Radiation Therapy and Dosimetry
- Radiation Detection and Scintillator Technologies
- Dark Matter and Cosmic Phenomena
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Neutrino Physics Research
- Nuclear reactor physics and engineering
- Radiation Effects in Electronics
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Radioactivity and Radon Measurements
- Magnetic confinement fusion research
- Advanced Optical Sensing Technologies
- Electron and X-Ray Spectroscopy Techniques
- Photocathodes and Microchannel Plates
- Advanced Frequency and Time Standards
- Muon and positron interactions and applications
- Black Holes and Theoretical Physics
- Advanced Semiconductor Detectors and Materials
Brookhaven National Laboratory
2012-2024
K Lab (United States)
2019-2024
University of Geneva
2009
Eiken Chemical (Japan)
2009
Institute for Theoretical and Experimental Physics
2009
New Mexico State University
2009
Brookhaven College
2009
Los Alamos National Laboratory
2009
RIKEN
2009
RIKEN BNL Research Center
2009
During an energy scan at the Cornell Electron Storage Ring, with use of Columbia University-Stony Brook NaI detector, enhancement in $\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons})$ is observed center-of-mass \ensuremath{\sim}10.55 GeV. The mass and leptonic width this state (${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}\ensuremath{'}}$) suggest that it $4^{3}S_{1}$ bound $b$ quark its antiquark. After applying to data a cut (pseudo) thrust...
The $\ensuremath{\Upsilon}$, ${\ensuremath{\Upsilon}}^{\ensuremath{'}}$, and ${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}}$ states have been observed at the Cornell Electron Storage Ring as narrow peaks in $\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons})$ versus beam energy. Data were collected during a run with integrated luminosity of 1000 ${\mathrm{nb}}^{\ensuremath{-}1}$, using Columbia University-Stony Brook segmented NaI detector....
We report a measurement of the ${\mathit{D}}^{\mathrm{*}+}$ and ${\mathit{D}}^{\mathrm{*}0}$ decay branching fractions based on 780 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ data collected with CLEO II detector. For radiative decay, we obtain an upper limit, scrB(${\mathit{D}}^{\mathrm{*}+}$\ensuremath{\rightarrow}${\mathit{D}}^{+}$\ensuremath{\gamma})4.2% (90% confidence level), which is substantially below previous results, eliminates need for anomalously large charm quark magnetic moment.
In a continuing study of the spectroscopy $b\overline{b}$ bound quark systems discovery lowest $P$-wave states by observation photons from decays $2^{3}S_{1}(b\overline{b})\ensuremath{\rightarrow}\ensuremath{\gamma}+1^{3}P_{J}(b\overline{b})$ and $1^{3}P_{J}(b\overline{b})\ensuremath{\rightarrow}\ensuremath{\gamma}+1^{3}S_{1}(b\overline{b})$ is reported. The are observed as narrow enhancements in inclusive photon spectrum ${\ensuremath{\Upsilon}}^{\ensuremath{'}}$ decays. center gravity...
Using the CLEO II detector and a sample of 955 000 \ensuremath{\Upsilon}(4S) decays we have confirmed charmless semileptonic B mesons. In momentum interval 2.3--2.6 GeV/c observe an excess 107\ifmmode\pm\else\textpm\fi{}15\ifmmode\pm\else\textpm\fi{}11 leptons, which attribute to b\ensuremath{\rightarrow}ul\ensuremath{\nu}. This result yields model-dependent range values for \ensuremath{\Vert}${\mathit{V}}_{\mathit{u}\mathit{b}}$/${\mathit{V}}_{\mathit{c}\mathit{b}}$\ensuremath{\Vert} that...
We have measured the B0B¯0 mixing probability, χd, using a sample of 965 000 BB¯ pairs from Υ(4S) decays. Counting dilepton events, we find χd=0.157±0.016±0.018−0.021+0.028. Using tagged B0 χd=0.149±0.023±0.019±0.010. The first (second) error is statistical (systematic). third reflects ±15% uncertainty in assumption, made both cases, that charged and neutral B contribute equally to events. also obtain limit on CP impurity Bd0 system, ‖Re(εB0)‖<0.045 at 90% C.L.Received 29 April...
The existence of $P$-wave $b\overline{b}$ bound states ${{\ensuremath{\chi}}_{b}}^{\ensuremath{'}}$ is demonstrated by observation photons from the transition ${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}+{{\ensuremath{\chi}}_{b}}^{\ensuremath{'}}$ in inclusive photon spectrum ${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}}$ decays. center gravity observed energies 98 MeV and branching ratio for to...
We present measurements of spectral moments extracted from the invariant mass distributions final states hadronic τ decay products recorded in CLEO detector. From a fit theoretical predictions to and total width τ, we determine strong coupling constant set non-perturbative QCD parameters. The is measured be αs(mτ) = 0.306 ± 0.024, which when extrapolated Z mass, yields αs(Mz) 0.114 0.003.
The CUSB detector at the Cornell Electron Storage Ring has been used to measure $R=\frac{\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons})}{\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})}$ in c.m. energy regions between ${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}}$ and ${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}\ensuremath{'}}$, above...
Using the CLEO II detector, we have measured branching fractions for $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\Upsilon}(1S)$, $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\Upsilon}(2S)$, and cascade $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\Upsilon}(2S)+X$,...
The decay ${\mathrm{\ensuremath{\tau}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\ensuremath{\nu}}_{\mathrm{\ensuremath{\tau}}}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\pi}}}^{0}$\ensuremath{\eta} has been observed for the first time using CLEO-II detector at Cornell Electron Storage Ring. measured branching ratio (0.17\ifmmode\pm\else\textpm\fi{}0.02\ifmmode\pm\else\textpm\fi{}0.02)%, agrees with CVC (conserved vector current) prediction based...
In a sample of 10 000 ${\ensuremath{\Upsilon}}^{\ensuremath{'}}$ decays observed with our nonmagnetic detector at the Cornell Electron Storage Ring, we find 23 events consistent decay ${\ensuremath{\Upsilon}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\Upsilon}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. We derive branching fraction...
Using the Colubia University---Stony Brook detector we have measured production of energetic electrons ($E>1$ GeV) in ${e}^{+}{e}^{\ensuremath{-}}$ annihilations center-of-mass energy range 10.4 to 11.4 GeV. We observe an enhanced electron signal at ${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}\ensuremath{'}}(4S)$ resonance, which interpret as evidence for $\ensuremath{\beta}$ decay a new flavor quark, $b$, bound within meson, $B$. derive branching ratio...
We have used the CUSB detector at Cornell Electron Storage Ring to study decays of $\ensuremath{\Upsilon}(1S)$ and $\ensuremath{\Upsilon}(3S)$ resonances into a single photon plus long-lived noninteracting particle. obtain an upper limit on branching ratio for $\ensuremath{\Upsilon}(1S)\ensuremath{\rightarrow}\ensuremath{\gamma}+X$, where $X$ is undetected. This 3.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ (90% C.L.) masses ${m}_{X}$ less than 7 GeV. For...