J. Fast

ORCID: 0000-0003-2258-701X
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About
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Research Areas
  • Particle physics theoretical and experimental studies
  • Quantum Chromodynamics and Particle Interactions
  • High-Energy Particle Collisions Research
  • Dark Matter and Cosmic Phenomena
  • Neutrino Physics Research
  • Particle Detector Development and Performance
  • Radiation Detection and Scintillator Technologies
  • Particle Accelerators and Free-Electron Lasers
  • Atomic and Subatomic Physics Research
  • Nuclear Physics and Applications
  • Astrophysics and Cosmic Phenomena
  • Nuclear physics research studies
  • Superconducting Materials and Applications
  • Black Holes and Theoretical Physics
  • Computational Physics and Python Applications
  • Medical Imaging Techniques and Applications
  • Particle accelerators and beam dynamics
  • Radioactivity and Radon Measurements
  • Radioactive contamination and transfer
  • Cosmology and Gravitation Theories
  • Muon and positron interactions and applications
  • Atomic and Molecular Physics
  • Scientific Research and Discoveries
  • Nuclear reactor physics and engineering
  • Superconducting and THz Device Technology

Pacific Northwest National Laboratory
2014-2024

Thomas Jefferson National Accelerator Facility
2019-2024

University of Cincinnati
1999-2020

University of the Basque Country
2013-2020

University of Florida
2000-2020

Duke University
2020

Chonnam National University
2018-2020

Battelle
2012-2019

Institut National de Physique Nucléaire et de Physique des Particules
2005-2018

Centre National de la Recherche Scientifique
2005-2018

We report on several features in the energy spectrum from an ultralow-noise germanium detector operated deep underground. By implementing a new technique able to reject surface events, number of cosmogenic peaks can be observed for first time. discuss irreducible excess bulklike events below 3 keV ionization energy. These could caused by unknown backgrounds, but also dark matter interactions consistent with DAMA/LIBRA. It is not yet possible determine their origin. Improved constraints are...

10.1103/physrevlett.106.131301 article EN publisher-specific-oa Physical Review Letters 2011-03-29

The cross section for ee+ e- → π+ π- J/ψ between 3.8 and 5.5 GeV is measured with a 967 fb(-1) data sample collected by the Belle detector at or near Υ(nS) (n = 1,2,…,5) resonances. Y(4260) state observed, its resonance parameters are determined. In addition, an excess of production around 4 observed. This feature can be described Breit-Wigner parametrization properties that consistent Y(4008) was previously reported Belle. study decays, structure observed in M(π(±)J/ψ) mass spectrum 5.2σ...

10.1103/physrevlett.110.252002 article EN publisher-specific-oa Physical Review Letters 2013-06-17

We report the observation of two narrow structures in mass spectra pi+-Y(nS) (n=1,2,3) and pi+-hb(mP)(m$ (m=1,2) pairs that are produced association with a single charged pion Y(5S) decays. The measured masses widths averaged over five final states M_1=(10607.2+-2.0) MeV/c2, Gamma_1=(18.4+-2.4) MeV M_2=(10652.2+-1.5) Gamma_2=(11.5+-2.2) MeV. results obtained 121.4 1/fb data sample collected Belle detector vicinity resonance at KEKB asymmetric-energy e+e- collider.

10.1103/physrevlett.108.122001 article EN publisher-specific-oa Physical Review Letters 2012-03-20

We have measured the inclusive $b\ensuremath{\rightarrow}s\ensuremath{\gamma}$ branching ratio to be $(2.32\ifmmode\pm\else\textpm\fi{}0.57\ifmmode\pm\else\textpm\fi{}0.35)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, where first error is statistical and second systematic. Upper lower limits on ratio, each at 95% C.L., are $B(b\ensuremath{\rightarrow}s\ensuremath{\gamma})<4.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$...

10.1103/physrevlett.74.2885 article EN Physical Review Letters 1995-04-10

Fifteen months of cumulative CoGeNT data are examined for indications an annual modulation, a predicted signature weakly interacting massive particle (WIMP) interactions. Presently available support the presence modulated component unknown origin, with parameters prima facie compatible galactic halo composed light-mass WIMPs. Unoptimized estimators yield statistical significance modulation ∼2.8σ, limited by short exposure.

10.1103/physrevlett.107.141301 article EN publisher-specific-oa Physical Review Letters 2011-09-26

We have observed the decays ${\mathit{B}}^{0}$\ensuremath{\rightarrow}${\mathit{K}}^{\mathrm{*}}$(892${)}^{0}$\ensuremath{\gamma} and ${\mathit{B}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathit{K}}^{\mathrm{*}}$(892${)}^{\mathrm{\ensuremath{-}}}$\ensuremath{\gamma}, which are evidence for quark-level process b\ensuremath{\rightarrow}s\ensuremath{\gamma}. The average branching fraction is...

10.1103/physrevlett.71.674 article EN Physical Review Letters 1993-08-02

CoGeNT employs p-type point-contact (PPC) germanium detectors to search for Weakly Interacting Massive Particles (WIMPs). By virtue of its low energy threshold and ability reject surface backgrounds, this type device allows an emphasis on low-mass dark matter candidates (wimp mass about 10 GeV/c2). We report the characteristics PPC detector presently taking data at Soudan Underground Laboratory, elaborating aspects shielding, acquisition, instrumental stability, analysis, background...

10.1103/physrevd.88.012002 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2013-07-08

We report a measurement of the ratio ${\cal R}(D^*) = {\cal B}(\bar{B}^0 \rightarrow D^{*+} \tau^- \bar{\nu}_{\tau})/{\cal \ell^- \bar{\nu}_{\ell})$, where $\ell$ denotes an electron or muon. The results are based on data sample containing $772\times10^6$ $B\bar{B}$ pairs recorded at $\Upsilon(4S)$ resonance with Belle detector KEKB $e^+ e^-$ collider. select $B^0 \bar{B}^0$ by reconstructing both $B$ mesons in semileptonic decays to $D^{*\mp} \ell^{\pm}$. measure R}(D^*)= 0.302 \pm...

10.1103/physrevd.94.072007 article EN publisher-specific-oa Physical review. D/Physical review. D. 2016-10-27

The M ajorana D emonstrator will search for the neutrinoless double-beta<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mo stretchy="false">(</mml:mo><mml:mi>β</mml:mi><mml:mi>β</mml:mi><mml:mfenced separators="|"><mml:mrow><mml:mn fontstyle="italic">0</mml:mn><mml:mi>ν</mml:mi></mml:mrow></mml:mfenced><mml:mo stretchy="false">)</mml:mo></mml:math>decay of isotope<mml:math id="M2"/>Ge with a mixed array enriched and natural germanium detectors. observation this rare...

10.1155/2014/365432 article EN cc-by Advances in High Energy Physics 2014-01-01

We report a measurement of the process $\ensuremath{\gamma}{\ensuremath{\gamma}}^{*}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}$ with $759\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample recorded Belle detector at KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. The pion transition form factor, $F({Q}^{2})$, is measured for kinematical region $4\text{ }{\mathrm{GeV}}^{2}\ensuremath{\lesssim}{Q}^{2}\ensuremath{\lesssim}40\text{ }{\mathrm{GeV}}^{2}$, where...

10.1103/physrevd.86.092007 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2012-11-09

We perform a full amplitude analysis of B0→ψ′K+π− decays, with ψ′→μ+μ− or e+e−, to constrain the spin and parity Z(4430)−. The JP=1+ hypothesis is favored over 0−, 1−, 2− 2+ hypotheses at levels 3.4σ, 3.7σ, 4.7σ 5.1σ, respectively. based on 711 fb−1 data sample that contains 772×106 BB¯ pairs collected Υ(4S) resonance by Belle detector asymmetric-energy e+e− collider KEKB.7 MoreReceived 20 June 2013DOI:https://doi.org/10.1103/PhysRevD.88.074026© 2013 American Physical Society

10.1103/physrevd.88.074026 article EN Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2013-10-22

We present results from a study of $X(3872)\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}J/\ensuremath{\psi}$ decays produced via exclusive $B\ensuremath{\rightarrow}KX(3872)$ decays. determine the mass to be ${M}_{X(3872)}=(3871.85\ifmmode\pm\else\textpm\fi{}0.27(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.19(\mathrm{syst}))\text{ }\text{ }\mathrm{MeV}$, 90% confidence level upper limit on natural width ${\ensuremath{\Gamma}}_{X(3872)}<1.2\text{ product branching fraction...

10.1103/physrevd.84.052004 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2011-09-07

We report the first observations of spin-singlet bottomonium states hb(1P) and hb(2P). The are produced in reaction e+e−→hb(nP)π+π− using a 121.4 fb−1 data sample collected at energies near Υ(5S) resonance with Belle detector KEKB asymmetric-energy e+e− collider. determine M[hb(1P)]=(9898.2+1.1+1.0−1.0−1.1) MeV/c2 M[hb(2P)]=(10 259.8±0.6+1.4−1.0) MeV/c2, which correspond to P-wave hyperfine splittings ΔMHF=(+1.7±1.5) (+0.5+1.6−1.2) respectively. significances hb(2P) 5.5σ 11.2σ, find that...

10.1103/physrevlett.108.032001 article EN publisher-specific-oa Physical Review Letters 2012-01-18

A claim for evidence of dark matter interactions in the DAMA experiment has been recently reinforced. We employ a new type germanium detector to conclusively rule out standard isothermal galactic halo weakly interacting massive particles as explanation annual modulation effect leading claim. Bounds are similarly imposed on suggestion that pseudoscalars might lead effect. describe sensitivity light achievable with our device, particular, next-to-minimal supersymmetric model candidates.

10.1103/physrevlett.101.251301 article EN Physical Review Letters 2008-12-17

We present a determination of the magnitude Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ using decay $B\to D\ell\nu_\ell$ ($\ell=e,\mu$) based on 711 fb$^{-1}$ $e^+e^-\to \Upsilon(4S)$ data recorded by Belle detector and containing $772 \times 10^6$ $B\bar{B}$ pairs. One $B$ meson in event is fully reconstructed hadronic mode while other, signal side, partially from charged lepton either $D^+$ or $D^0$ total 23 modes. The isospin-averaged branching fraction found to be...

10.1103/physrevd.93.032006 article EN publisher-specific-oa Physical review. D/Physical review. D. 2016-02-25

We report on a search for heavy neutrinos in B-meson decays. The results are obtained using data sample that contains 772x10^6 BB-bar pairs collected at the Upsilon(4S) resonance with Belle detector KEKB asymmetric-energy e+e- collider. No signal is observed and upper limits set mixing of left-handed Standard Model mass range 0.5 - 5.0 GeV/c^2.

10.1103/physrevd.87.071102 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2013-04-22

We present a measurement of angular observables and test lepton flavor universality in the $B\to K^\ast \ell^+\ell^-$ decay, where $\ell$ is either $e$ or $μ$. The analysis performed on data sample corresponding to an integrated luminosity $711~\mathrm{fb}^{-1}$ containing $772\times 10^{6}$ $B\bar B$ pairs, collected at $Υ(4S)$ resonance with Belle detector asymmetric-energy $e^+e^-$ collider KEKB. result consistent Standard Model (SM) expectations, largest discrepancy from SM prediction...

10.48550/arxiv.1612.05014 preprint EN other-oa arXiv (Cornell University) 2016-01-01

We present a measurement of angular observables, $P_4'$, $P_5'$, $P_6'$, $P_8'$, in the decay $B^0 \to K^\ast(892)^0 \ell^+ \ell^-$, where $\ell^+\ell^-$ is either $e^+e^-$ or $\mu^+\mu^-$. The analysis performed on data sample corresponding to an integrated luminosity $711~\mathrm{fb}^{-1}$ containing $772\times 10^{6}$ $B\bar B$ pairs, collected at $\Upsilon(4S)$ resonance with Belle detector asymmetric-energy collider KEKB. Four $P_{4,5,6,8}'$ are extracted five bins invariant mass...

10.48550/arxiv.1604.04042 preprint EN other-oa arXiv (Cornell University) 2016-01-01

We report a search for the rare decays $B\ensuremath{\rightarrow}{h}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, where ${h}^{(*)}$ stands ${K}^{+}$, ${K}_{S}^{0}$, ${K}^{*+}$, ${K}^{*0}$, ${\ensuremath{\pi}}^{+}$, ${\ensuremath{\pi}}^{0}$, ${\ensuremath{\rho}}^{+}$, ${\ensuremath{\rho}}^{0}$ and $\ensuremath{\phi}$. The results are obtained from $711\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample that contains $772\ifmmode\times\else\texttimes\fi{}{10}^{6}B\overline{B}$...

10.1103/physrevd.87.111103 article EN publisher-specific-oa Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology 2013-06-27

We present a precise measurement of the CP violation parameter sin2phi_1 and direct A_f using final data sample 772x10^6 B\bar B pairs collected at Upsilon(4S) resonance with Belle detector KEKB asymmetric-energy e+e- collider. One neutral meson is reconstructed in J/psi K0S, psi(2S) chi_c1 K0S or K0L CP-eigenstate its flavor identified from decay products accompanying meson. From distribution proper time intervals between two decays, we obtain following parameters:...

10.1103/physrevlett.108.171802 article EN publisher-specific-oa Physical Review Letters 2012-04-23

Using the entire Belle data sample of 980 ${\rm fb}^{-1}$ $e^+e^-$ collisions, we present results a study excited $\Omega_c$ charmed baryons in decay mode $\Xi_c^+K^-$. We show confirmation four five narrow states reported by LHCb Collaboration: $\Omega_c(3000)$ , $\Omega_c(3050)$, $\Omega_c(3066)$, and $\Omega_c(3090)$.

10.1103/physrevd.97.051102 article EN cc-by Physical review. D/Physical review. D. 2018-03-09

We report on a study of the invariant mass spectrum hadronic system in decay ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}}.$ This was performed with data obtained CLEO II detector operating at CESR ${e}^{+}{e}^{\ensuremath{-}}$ collider. present fits to phenomenological models which resonance parameters associated $\ensuremath{\rho}(770)$ and $\ensuremath{\rho}(1450)$ mesons are...

10.1103/physrevd.61.112002 article EN Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 2000-05-03

We have performed a search for the 1P1 state of charmonium resonantly formed in p¯p annihilations, close to center gravity 3PJ states. report results from study J/ψ+π0 and J/ψ+2π final observed statistically significant enhancement p¯+p→J/ψ+π0 cross section at √s ≃3526.2 MeV. This has characteristics narrow resonance mass, total width, production consistent with what is expected state. In our we found no candidates reactions p¯+p→J/ψ+π0+π0 p¯+p→J/ψ+π++π−.Received 10 July...

10.1103/physrevlett.69.2337 article EN Physical Review Letters 1992-10-19

We report measurements of B→χ(c1)γK and χ(c2)γK decays using 772×10(6) BB[over ¯] events collected at the Υ(4S) resonance with Belle detector KEKB asymmetric-energy e(+)e(-) collider. Evidence a new in χ(c1)γ final state is found statistical significance 3.8σ. This has mass 3823.1±1.8(stat)±0.7(syst) MeV/c(2), value that consistent theoretical expectations for previously unseen 1(3)D(2) cc[over meson. find no other narrow set upper limits on branching fractions X(3872)→χ(c1)γ χ(c2)γ decays.

10.1103/physrevlett.111.032001 article EN publisher-specific-oa Physical Review Letters 2013-07-16
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