A5009369438- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Particle accelerators and beam dynamics
- Neutrino Physics Research
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Muon and positron interactions and applications
- Dark Matter and Cosmic Phenomena
- Advanced Chemical Physics Studies
- Particle Detector Development and Performance
- Inorganic Fluorides and Related Compounds
- Advanced NMR Techniques and Applications
- Quantum, superfluid, helium dynamics
- Medical Imaging Techniques and Applications
- Magnetic confinement fusion research
- NMR spectroscopy and applications
- Physics of Superconductivity and Magnetism
- Machine Learning in Materials Science
- Advanced Electrical Measurement Techniques
- Advanced X-ray Imaging Techniques
Fermi National Accelerator Laboratory
2018-2024
Florida International University
2011-2021
Rice University
2016-2018
University of Minnesota
2018
Institut de Physique
2014
Campbell Collaboration
2013-2014
Tohoku University
2013
We present the first results of Fermilab Muon g-2 Experiment for positive muon magnetic anomaly $a_\mu \equiv (g_\mu-2)/2$. The is determined from precision measurements two angular frequencies. Intensity variation high-energy positrons decays directly encodes difference frequency $\omega_a$ between spin-precession and cyclotron frequencies polarized muons in a storage ring. ring field measured using nuclear resonance probes calibrated terms equivalent proton spin precession...
We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling ${\ensuremath{\alpha}}^{\ensuremath{'}}$ to electrons. Such particle ${A}^{\ensuremath{'}}$ can be produced in electron-nucleus fixed-target scattering and then decay an ${e}^{+}{e}^{\ensuremath{-}}$ pair, producing narrow resonance QED trident spectrum. Using APEX test run data, we searched mass range 175--250 MeV, found no evidence...
We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. have analyzed more than 4 times number positrons decay our previous result 2018 data. The systematic error is reduced by factor 2 due to better running conditions, stable beam, improved knowledge field weighted distribution, ω[over ˜]_{p}^{'}, anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From ratio...
The Muon g-2 Experiment at Fermi National Accelerator Laboratory (FNAL) has measured the muon anomalous precession frequency $ω_a$ to an uncertainty of 434 parts per billion (ppb), statistical, and 56 ppb, systematic, with data collected in four storage ring configurations during its first physics run 2018. When combined a precision measurement magnetic field experiment's ring, determines anomaly $a_μ({\rm FNAL}) = 116\,592\,040(54) \times 10^{-11}$ (0.46 ppm). This article describes...
The reaction gamma + p -> K+ Sigma pi was used to determine the invariant mass distributions or "line shapes" of Sigma+ pi-, Sigma- pi+ and Sigma0 pi0 final states, from threshold at 1328 MeV/c^2 through range Lambda(1405) Lambda(1520). measurements were made with CLAS system Jefferson Lab using tagged real photons, for center-of-mass energies 1.95 < W 2.85 GeV. three differ strongly in vicinity I=0 \Lambda(1405), indicating presence substantial I=1 strength reaction. Background...
There is a significant discrepancy between the values of proton electric form factor, G(E)(p), extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect extraction G(E)(p) from electron-proton cross sections. We determined TPE contribution by measuring ratio positron-proton to elastic scattering sections simultaneous, tertiary electron-positron beam incident on liquid hydrogen target...
The Fermi National Accelerator Laboratory has measured the anomalous precession frequency $a^{}_\mu = (g^{}_\mu-2)/2$ of muon to a combined precision 0.46 parts per million with data collected during its first physics run in 2018. This paper documents measurement magnetic field storage ring. is monitored by nuclear resonance systems and calibrated terms equivalent proton spin spherical water sample at 34.7$^\circ$C. weighted distribution resulting $\tilde{\omega}'^{}_p$, denominator ratio...
We present details on a new measurement of the muon magnetic anomaly, $a_\mu = (g_\mu -2)/2$. The result is based positive data taken at Fermilab's Muon Campus during 2019 and 2020 accelerator runs. uses $3.1$ GeV$/c$ polarized muons stored in $7.1$-m-radius storage ring with $1.45$ T uniform field. value $ a_{\mu}$ determined from measured difference between spin precession frequency its cyclotron frequency. This normalized to strength field, using Nuclear Magnetic Resonance (NMR). ratio...
We report the exclusive photoproduction cross sections for Sigma(1385), Lambda(1405), and Lambda(1520) in reactions gamma + p -> K+ Y* using CLAS detector energies from near respective production thresholds up to a center-of-mass energy W of 2.85 GeV. The differential are integrated give total each hyperon. Comparisons made current theoretical models based on effective Lagrangian approach fitted previous data. accuracy these is seen vary widely. Lambda(1405) region strikingly different...
Spectroscopy of a $^{10}_{\Lambda}$Be hypernucleus was carried out at JLab Hall C using the $(e,e^{\prime}K^{+})$ reaction. A new magnetic spectrometer system (SPL+HES+HKS), specifically designed for high resolution hypernuclear spectroscopy, used to obtain an energy spectrum with 0.78 MeV (FWHM). The well-calibrated present experiment $p(e,e^{\prime}K^{+})\Lambda,\Sigma^{0}$ reactions allowed us determine levels, and binding ground state peak (mixture 1$^{-}$ 2$^{-}$ states) obtained be...
High-statistics measurements of differential cross sections and spin density matrix elements for the reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}\ensuremath{\phi}p$ have been made using CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.97 to 2.84 GeV, with an extensive coverage in $\ensuremath{\phi}$ production angle. The high statistics data sample it necessary carefully account interplay between natural lineshape effects resolution, that are...
We present a new measurement of the positive muon magnetic anomaly, $a_\mu \equiv (g_\mu - 2)/2$, from Fermilab Muon $g\!-\!2$ Experiment using data collected in 2019 and 2020. have analyzed more than 4 times number positrons decay our previous result 2018 data. The systematic error is reduced by factor 2 due to better running conditions, stable beam, improved knowledge field weighted distribution, $\tilde{\omega}'^{}_p$, anomalous precession frequency corrected for beam dynamics effects,...
A determination of the spin and parity Λ(1405) is presented using photoproduction data from CLAS detector at Jefferson Lab. The reaction γ+p→K++Λ(1405) analyzed in decay channel Λ(1405)→Σ++π−, where distribution to Σ+π− variation Σ+ polarization with respect direction determines parity. produced, energy range 2.55<W<2.85 GeV for 0.6<cosθc.m.K+<0.9, P=0.45±0.02(stat)±0.07(syst). analysis shows that decays are S wave, polarized such has spin-parity JP=12−, as expected by most theories.Received...
Since the pioneering experiment, E89-009 studying hypernuclear spectroscopy using $(e,e^{\prime}K^+)$ reaction was completed, two additional experiments, E01-011 and E05-115, were performed at Jefferson Lab. These later experiments used a modified experimental design, "tilt method", to dramatically suppress large electromagnetic background, allowed for substantial increase in luminosity. Additionally, new kaon spectrometer, HKS (E01-011), electron HES, splitting magnet added produce...
Differential cross sections of the exclusive process $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}n$ were measured with good precision in range photon virtuality ${Q}^{2}=1.8--4.5$ ${\mathrm{GeV}}^{2}$ and invariant mass ${\ensuremath{\pi}}^{+}n$ final state $W=1.6--2.0$ GeV using Continuous Electron Beam Accelerator Facility Large Acceptance Spectrometer. Data collected nearly complete coverage azimuthal polar angles $n{\ensuremath{\pi}}^{+}$ center-of-mass system....
A measurement of the electroproduction photons off protons in deeply inelastic regime was performed at Jefferson Lab using a nearly 6 GeV electron beam, longitudinally polarized proton target, and CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for ep→e^{'}p^{'}γ events, which arise from interference virtual Compton scattering Bethe-Heitler processes, were extracted over widest kinematics Q^{2}, x_{B}, t, ϕ, 166 four-dimensional bins. In framework generalized parton...
The inclusive polarized structure functions of the proton and deuteron, g1p g1d, were measured with high statistical precision using 6 GeV electrons incident on a ammonia target in Hall B at Jefferson Laboratory. Electrons scattered lab angles between 18 45 degrees detected CEBAF Large Acceptance Spectrometer (CLAS). For usual DIS kinematics, Q^2>1 GeV^2 final-state invariant mass W>2 GeV, ratio to unpolarized g1/F1 is found be nearly independent Q^2 fixed x. Significant resonant apparent...
Exclusive neutral-pion electroproduction ($ep\to e^\prime p^\prime \pi^0$) was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^4\sigma/dtdQ^2dx_Bd\phi_\pi$ structure functions $\sigma_T+\epsilon\sigma_L, \sigma_{TT}$ $\sigma_{LT}$ as of $t$ were obtained over wide range $Q^2$ $x_B$. The data are compared Regge handbag theoretical calculations. Analyses in both frameworks find that large dominance transverse processes is necessary...
We report the first measurement of photoproduction cross section $\phi$ meson in its neutral decay mode reaction $\gamma p \to p\phi(K_SK_L)$. The experiment was performed with a tagged photon beam energy $1.6 \le E_\gamma 3.6$ GeV incident on liquid hydrogen target CLAS spectrometer at Thomas Jefferson National Accelerator Facility. $p \phi$ final state is identified via reconstruction $K_S$ invariant mass two oppositely charged pions and by requiring missing particle K_S X$ to be $K_L$....
We have measured the moment ALUsinϕ corresponding to polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering. is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with CLAS Spectrometer at Jefferson Lab using 5.498 GeV longitudinally beam and an unpolarized liquid hydrogen target. All three pion channels (π+, π0 π−) simultaneously over large range of kinematics within virtuality Q2≈ 1.0–4.5 GeV2. The observable was better than...
The missing mass spectroscopy of the $^{7}_{\Lambda}$He hypernucleus was performed, using $^{7}$Li$(e,e^{\prime}K^{+})^{7}_{\Lambda}$He reaction at Thomas Jefferson National Accelerator Facility Hall C. $\Lambda$ binding energy ground state (1/2$^{+}$) determined with a smaller error than that previous measurement, being $B_{\Lambda}$ = 5.55 $\pm$ 0.10(stat.) 0.11(sys.) MeV. experiment also provided new insight into charge symmetry breaking in p-shell hypernuclear systems. Finally, peak 3.65...
Background: The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations TPE corrections have significant model dependence, there limited direct experimental evidence for such corrections.Purpose: contributions depend on sign lepton charge in ${e}^{\ifmmode\pm\else\textpm\fi{}}p$ scattering, but luminosities secondary positron beams past...
Received 15 October 2013DOI:https://doi.org/10.1103/PhysRevC.88.049902©2013 American Physical Society
We report measurements of the exclusive electroproduction $K^+\Lambda$ and $K^+\Sigma^0$ final states from an unpolarized proton target using CLAS detector at Thomas Jefferson National Accelerator Facility. The separated structure functions $\sigma_U$, $\sigma_{LT}$, $\sigma_{TT}$, $\sigma_{LT'}$ were extracted $\Phi$-dependent differential cross sections acquired with a longitudinally polarized 5.499 GeV electron beam. data span broad range momentum transfers $Q^2$ 1.4 to 3.9 GeV$^2$,...