K. L. Giovanetti
A5016304695- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Dark Matter and Cosmic Phenomena
- Atomic and Molecular Physics
- Advanced NMR Techniques and Applications
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Muon and positron interactions and applications
- Medical Imaging Techniques and Applications
- Neutrino Physics Research
- X-ray Spectroscopy and Fluorescence Analysis
- Superconducting Materials and Applications
- Scientific Research and Discoveries
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Radioactive Decay and Measurement Techniques
- Nuclear Physics and Applications
- Scientific Measurement and Uncertainty Evaluation
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
James Madison University
2014-2024
Duquesne University
2020
Argonne National Laboratory
2015-2018
Carrier (United States)
2017
Thomas Jefferson National Accelerator Facility
2017
University of Bonn
2017
Campbell Collaboration
2004-2014
Florida State University
2006
Institute of Nuclear and Particle Physics
1993
ETH Zurich
1985-1987
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...
In an exclusive measurement of the reaction gammad-->K(+)K(-)pn, a narrow peak that can be attributed to exotic baryon with strangeness S=+1 is seen in K(+)n invariant mass spectrum. The at 1.542+/-0.005 GeV/c(2) measured width 0.021 FWHM, which largely determined by experimental resolution. statistical significance (5.2+/-0.6)sigma. and observed are consistent recent reports other groups.
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...
High-statistics cross sections for the reactions gamma + p --> K^+ Lambda and Sigma^0 have been measured using CLAS at Jefferson Lab center-of-mass energies W between 1.6 2.53 GeV, -0.85 < cos theta_{K^+}^{c.m.}< +0.95. In channel we confirm a resonance-like structure near W=1.9 GeV backward kaon angles. The position width of this change with angle, indicating that more than one resonance is likely playing role. forward angles all well described by t-channel scaling characteristic Regge...
The ratios of inclusive electron scattering cross sections 4He, 12C, and 56Fe to 3He have been measured at 1<xB<3. At Q2>1.4 GeV2, the exhibit two separate plateaus, 1.5<xB<2 xB>2.25. This pattern is predicted by models that include 2- 3-nucleon short-range correlations (SRC). Relative A=3, per-nucleon probabilities SRC are 2.3, 3.1, 4.4 times larger for A=4, 12, 56. first measurement in nuclei.Received 16 August 2005DOI:https://doi.org/10.1103/PhysRevLett.96.082501©2006 American Physical Society
The reaction gamma p-->pi(+)K(-)K(+)n was studied at Jefferson Laboratory using a tagged photon beam with an energy range of 3-5.47 GeV. A narrow baryon state strangeness S=+1 and mass M=1555+/-10 MeV/c(2) observed in the nK(+) invariant spectrum. peak's width is consistent CLAS resolution (FWHM=26 MeV/c(2)), its statistical significance (7.8+/-1.0)sigma. positive has exotic structure cannot be described framework naive constituent quark model. predicted by chiral soliton model for Theta(+)...
We present results on the electroexcitation of low mass resonances Delta(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range Q2. The were obtained comprehensive analysis JLab-CLAS data differential cross sections, longitudinally polarized beam asymmetries, longitudinal target beam-target asymmetries for pion electroproduction off proton. analysed using two conceptually different approaches, fixed-t dispersion relations unitary isobar model, allowing us to draw conclusions model...
The beam-spin asymmetries in the hard exclusive electroproduction of photons on proton ($\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}ep\ensuremath{\gamma}$) were measured over a wide kinematic range and with high statistical accuracy. These result from interference Bethe-Heitler process deeply virtual Compton scattering. Over whole (${x}_{B}$ 0.11 to 0.58, ${Q}^{2}$ 1 $4.8\text{ }\text{ }{\mathrm{GeV}}^{2}$, $\ensuremath{-}t$ 0.09 $1.8\text{ }{\mathrm{GeV}}^{2}$),...
Cross-sections and recoil polarizations for the reactions gamma + p --> K^+ Lambda Sigma^0 have been measured with high statistics good angular coverage center-of-mass energies between 1.6 2.3 GeV. In K^+Lambda channel we confirm a structure near W=1.9 GeV at backward kaon angles, but our data shows more complex s- u- resonance than previously seen. This is present forward angles not central its position width change angle, indicating that one playing role. Rising back-angle cross sections...
We present measurements of the differential cross section and $\ensuremath{\Lambda}$ recoil polarization for $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{+}\ensuremath{\Lambda}$ reaction made using CLAS detector at Jefferson Lab. These cover center-of-mass energy range from $1.62$ to $2.84$ GeV a wide ${K}^{+}$ production angles. Independent analyses were performed ${K}^{+}p{\ensuremath{\pi}}^{\ensuremath{-}}$ ${K}^{+}p$ (missing ${\ensuremath{\pi}}^{\ensuremath{-}}$) final-state...
Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}+p\ensuremath{\rightarrow}{K}^{+}+\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Lambda}}$ and $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}+p\ensuremath{\rightarrow}{K}^{+}+{\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Sigma}}}^{0}$. The data were obtained using CEBAF Large Acceptance Spectrometer (CLAS)...
The transition helicity amplitudes from the proton ground state to $P_{11}(1440)$ and $D_{13}(1520)$ excited states ($\gamma_{v}pN^*$ electrocouplings) were determined analysis of nine independent one-fold differential $\pi^{+} \pi^{-} p$ electroproduction cross sections off a target, taken with CLAS at photon virtualities 0.25\enskip {\rm GeV$^{2}$} $<$ $Q^{2}$ 0.60 \enskip GeV$^{2}$}. phenomenological reaction model was employed for separation resonant non-resonant contributions final...
Unpolarized and beam-polarized fourfold cross sections (d^{4}σ/dQ^{2}dx_{B}dtdϕ) for the ep→e^{'}p^{'}γ reaction were measured using CLAS detector 5.75-GeV polarized electron beam of Jefferson Lab accelerator, 110 (Q^{2},x_{B},t) bins over widest phase space ever explored in valence-quark region. Several models generalized parton distributions (GPDs) describe data well at most our kinematics. This increases confidence that we understand GPD H, expected to be dominant contributor these...
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 a measurement of the positive muon lifetime to precision 1.0 ppm; it is most precise particle ever measured. The experiment used time-structured, low-energy beam and segmented plastic scintillator array record more than 2×1012 decays. Two different stopping target configurations were employed in independent data-taking periods. combined results give τμ+(MuLan)=2 196 980.3(2.2) ps, 15 times as any previous experiment. gives value for Fermi constant: GF(MuLan)=1.166 378 8(7)×10−5...
High-statistics differential cross sections for the reactions $\ensuremath{\gamma}p\ensuremath{\rightarrow}p\ensuremath{\eta}$ and $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\eta}}^{'}$ have been measured using CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab center-of-mass energies from near threshold up to 2.84 GeV. The ${\ensuremath{\eta}}^{'}$ results are most precise date provide largest energy angular coverage. $\ensuremath{\eta}$ measurements extend range of...
We present a detailed report of the method, setup, analysis and results precision measurement positive muon lifetime. The experiment was conducted at Paul Scherrer Institute using time-structured, nearly 100%-polarized, surface beam segmented, fast-timing, plastic scintillator array. employed two target arrangements; magnetized ferromagnetic with ~4 kG internal magnetic field crystal quartz in 130 G external field. Approximately 1.6 x 10^{12} positrons were accumulated together data yield...
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...
The cross section for the reaction ep-->e(')ppi(+)pi(-) was measured in resonance region 1.4<W<2.1 GeV and 0.5<Q2<1.5 GeV(2)/c(2) using CLAS detector at Jefferson Laboratory. data show resonant structures not visible previous experiments. comparison of our to a phenomenological prediction available information on N(*) Delta states shows an evident discrepancy. A better description is obtained either by sizable change properties P13(1720) or introducing new baryon state, reported published analyses.