S. Bouchigny
A5013137682- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Surgical Simulation and Training
- Quantum, superfluid, helium dynamics
- Augmented Reality Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Nuclear Physics and Applications
- Advanced NMR Techniques and Applications
- Tactile and Sensory Interactions
- Teleoperation and Haptic Systems
- Anatomy and Medical Technology
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Medical Imaging Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Adaptive optics and wavefront sensing
- Superconducting Materials and Applications
- Botulinum Toxin and Related Neurological Disorders
- Quantum chaos and dynamical systems
- Virtual Reality Applications and Impacts
- Particle accelerators and beam dynamics
- Motor Control and Adaptation
CEA LIST
2011-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2010-2024
Université Paris-Saclay
2024
CEA Paris-Saclay
1999-2023
Institut de Physique
2002-2011
Institut National de Physique Nucléaire et de Physique des Particules
2002-2011
CEA Paris-Saclay - Etablissement de Fontenay-aux-roses
2008-2011
Thomas Jefferson National Accelerator Facility
2001-2009
Université Paris-Sud
2007-2008
Centre National de la Recherche Scientifique
2008
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.
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...
We report the first results of beam-spin asymmetry measured in reaction $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}\mathrm{ep}\ensuremath{\gamma}$ at a beam energy 4.25 GeV. A large with $\mathrm{sin}\ensuremath{\varphi}$ modulation is observed, as predicted for interference term deeply virtual compton scattering (DVCS) and Bethe-Heitler process. The amplitude this...
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(+)...
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...
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 ratios of inclusive electron scattering cross sections $^4$He, $^{12}$C, and $^{56}$Fe to $^3$He have been measured for the first time. It is shown that these are independent $x_B$ at Q$^2>$1.4 (GeV/c)$^2$ $x_B>$ 1.5 where section depends primarily on high-momentum components nuclear wave function. observed scaling shows momentum distributions high-momenta same shape all nuclei differ only by a scale factor. onset $x_B >$1.5 consistent with kinematical expectation two nucleon short range...
We report the first evidence for a nonzero beam-spin azimuthal asymmetry in electroproduction of positive pions deep-inelastic kinematic region. Data reaction $e\stackrel{\ensuremath{\rightarrow}}{p}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}X$ have been obtained using polarized electron beam 4.3 GeV with CEBAF Large Acceptance Spectrometer at Thomas Jefferson National Accelerator Facility. The amplitude $\mathrm{sin}\ensuremath{\varphi}$ modulation increases momentum pion relative to virtual...
We report results for the virtual photon asymmetry $A_1$ on nucleon from new Jefferson Lab measurements. The experiment, which used CEBAF Large Acceptance Spectrometer and longitudinally polarized proton ($^{15}$NH$_3$) deuteron ($^{15}$ND$_3$) targets, collected data with a electron beam at energies between 1.6 GeV 5.7 GeV. In present paper, we concentrate our $A_1(x,Q^2)$ related ratio $g_1/F_1(x,Q^2)$ in resonance deep inelastic regions lowest highest energies, covering range momentum...
The neutron elastic magnetic form factor GMn has been extracted from quasielastic electron scattering data on deuterium with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. kinematic coverage of measurement is continuous Q2=1 GeV2 to 4.8 GeV2. High precision was achieved by employing a ratio technique in which many uncertainties cancel, and simultaneous in-situ calibration detection efficiency, largest correction data. Neutrons were detected using CLAS electromagnetic...
Differential cross sections for gammap-->etap have been measured with tagged real photons incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information protons scattered in the production process. The data provide first extensive angular distribution measurements process above W=1.75 Comparison preliminary results a constituent quark model support suggestion that third S11 resonance approximately 1.8 GeV couples etaN channel.
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.
The longitudinal target-spin asymmetry ${A}_{\mathrm{UL}}$ for the exclusive electroproduction of high-energy photons was measured first time in $e\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\rightarrow}{e}^{\ensuremath{'}}p\ensuremath{\gamma}$. data have been accumulated at JLab with CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized ${\mathrm{NH}}_{3}$ target. A significant azimuthal angular dependence observed, resulting from interference deeply virtual Compton...
We report a new measurement of the exclusive electroproduction reaction ${\ensuremath{\gamma}}^{*}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}p$ to explore evolution from soft nonperturbative physics hard processes via ${Q}^{2}$ dependence magnetic (${M}_{1+}$), electric (${E}_{1+}$), and scalar (${S}_{1+}$) multipoles in $N\ensuremath{\rightarrow}\ensuremath{\Delta}$ transition. 9000 differential cross section data points cover $W$ threshold $1.4\text{ }\text{ }\mathrm{GeV}/{c}^{2}$,...
A search for the Θ+ in reaction γd→pK−K+n was completed using CLAS detector at Jefferson Lab. study of same reaction, published earlier, reported observation a narrow resonance. The present experiment, with more than 30 times integrated luminosity our earlier measurement, does not show any evidence pentaquark angle-integrated upper limit on production mass range 1.52–1.56 GeV/c2 γd→pK−Θ+ is 0.3 nb (95% C.L.). This depends assumptions made and angular distribution production. Using Λ(1520) as...
New cross sections for the reaction $ep \to e'\eta p$ are reported total center of mass energy $W$=1.5--2.3 GeV and invariant squared momentum transfer $Q^2$=0.13--3.3 GeV$^2$. This large kinematic range allows extraction new information about response functions, photocouplings, $\eta N$ coupling strengths baryon resonances. A sharp structure is seen at $W\sim$ 1.7 GeV. The shape differential section indicative presence a $P$-wave resonance that persists to high $Q^2$. Improved values...
Differential cross sections for the reaction $\gamma p \to \pi^0$ have been measured with CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam energies from 0.675 to 2.875 GeV. The results reported here possess greater accuracy in absolute normalization than previous measurements. They disagree recent CB-ELSA measurements process at forward scattering angles. Agreement SAID MAID fits is found below 1 present set of has incorporated into database, exploratory extended 3...
The double π0 photoproduction off the proton has been measured in beam energy range of 0.65–1.5 GeV. total and differential cross sections Σ asymmetry were extracted. section for first time third resonance region nucleon shows a prominent peak. interpretation these results by two independent theoretical models infers mostly selective excitation P11- D13-nucleon resonances.Received 17 January 2003DOI:https://doi.org/10.1103/PhysRevLett.90.222001©2003 American Physical Society
The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. mesons, ρ, ω, and ϕ, are observed via their decay to e+e−, in order reduce effects final-state interactions nucleus. Of particular interest possible in-medium properties ρ meson. mass spectrum is extracted from data nuclei, 2H, C, Fe, Ti. We observe no significant shift some broadening consistent with expected collisional for meson.Received 20 July...
The exclusive reaction gammap-->K0K+n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of exotic baryon Theta+ (1540)-->nK+. decay to nK+requires assignment strangeness S=+1 any observed resonance. Data were collected with CLAS detector at Thomas Jefferson National Accelerator Facility corresponding an integrated luminosity 70 pb-1. No pentaquark found. Upper limits set on production cross section as function center-of-mass angle nK+ mass. 95% C.L. upper...
The helicity amplitudes of the electroexcitation Roper resonance are extracted for 1.7 < Q2 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data pi+ electroproduction on protons at W=1.15-1.69 GeV. analysis is made using two approaches, dispersion relations a unitary isobar model, which give consistent results. It found that transverse amplitude A_{1/2} gamma* p -> N(1440)P11 transition, large negative Q2=0, becomes positive ~ 2 GeV2,...
The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, iron targets a search for possible in-medium modifications to the properties of $\rho$ meson at normal nuclear densities zero temperature. detected with CEBAF Large Acceptance Spectrometer (CLAS) via their decays $e^{+}e^{-}$. rare leptonic decay was chosen reduce final-state interactions. A combinatorial background subtracted from invariant mass spectra using well-established event-mixing...