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Accueil > Recherche & Enseignement

M. Gilles Quéméner


Chercheur CNRS


Groupe : Interactions fondamentales et nature du neutrino


quemener lpccaen.in2p3.fr


Tél : +33 2 31 45 25 40



PUBLICATIONS

[in2p3-01199753] A revised experimental upper limit on the electric dipole moment of the neutron

18 février 2017

We present for the first time a detailed and comprehensive analysis of the experimental results that set the current world sensitivity limit on the magnitude of the electric dipole moment (EDM) of the neutron. We have extended and enhanced our earlier analysis to include recent developments in (...)

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[in2p3-01337513] Ultracold neutron detection with 6Li-doped glass scintillators, NANOSC: a fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute

2 novembre 2016

This paper summarizes the results from measurements aiming to characterize ultracold neutron detection with 6Li-doped glass scintillators. Single GS10 or GS20 scintillators, with a thickness of 100-200 micrometer, fulfill the ultracold neutron detection requirements with an acceptable (...)

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[in2p3-01213941] A highly stable atomic vector magnetometer based on free spin precession

15 décembre 2015

We present a magnetometer based on optically pumped Cs atoms that measures the magnitude and direction of a 1 $\mu$T magnetic field. Multiple circularly polarized laser beams were used to probe the free spin precession of the Cs atoms. The design was optimized for long-time stability and (...)

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[in2p3-01140188] Measurement of a false electric dipole moment signal from $^{199}$Hg atoms exposed to an inhomogeneous magnetic field

18 novembre 2015

We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for $^199\rm Hg$ atoms contained in a volume permeated with aligned magnetic and electric fields. This shift arises from the interplay between the inevitable magnetic field gradients and the (...)

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[in2p3-01120938] A device for simultaneous spin analysis of ultracold neutrons

18 novembre 2015

We report on the design and first tests of a device allowing for measurement of ultracold neutrons polarisation by means of the simultaneous analysis of the two spin components. The device was developed in the framework of the neutron electric dipole moment experiment at the Paul Scherrer (...)

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[in2p3-01159876] Observation of gravitationally induced vertical striation of polarized ultracold neutrons by spin-echo spectroscopy

19 octobre 2015

We describe a spin-echo method for ultracold neutrons (UCNs) confined in a precession chamber and exposed to a $|B_0|=1~\text\mu T$ magnetic field. We have demonstrated that the analysis of UCN spin-echo resonance signals in combination with knowledge of the ambient magnetic field provides an (...)

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[in2p3-01169555] Gravitational depolarization of ultracold neutrons: Comparison with data

9 octobre 2015

We compare the expected effects of so-called gravitationally enhanced depolarization of ultracold neutrons to measurements carried out in a spin-precession chamber exposed to a variety of vertical magnetic-field gradients. In particular, we have investigated the dependence upon these field (...)

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[in2p3-01079065] A measurement of the neutron to 199Hg magnetic moment ratio

1er juillet 2015

The neutron gyromagnetic ratio has been measured relative to that of the 199Hg atom with an uncertainty of 0.8 ppm. We employed an apparatus where ultracold neutrons and mercury atoms are stored in the same volume and report the result $\gamma_\rm n/\gamma_\rm Hg = (...)

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[in2p3-00868612] Electron shakeoff following the Β+ decay of trapped 35Ar+ ions

30 juin 2015

The electron shakeoff of $^35$Cl atoms resulting from the $\beta$$^+$ decay of $^35$Ar$^+$ ions has been investigated using a Paul trap coupled to a recoil-ion spectrometer. The charge-state distribution of the recoiling daughter nuclei is compared to theoretical calculations accounting for (...)

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[in2p3-01158512] Constraining interactions mediated by axion-like particles with ultracold neutrons

30 juin 2015

We report a new limit on a possible short range spin-dependent interaction from the precise measurement of the ratio of Larmor precession frequencies of stored ultracold neutrons and Hg-199 atoms confined in the same volume. The measurement was performed in a similar to 1 mu T vertical magnetic (...)

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[in2p3-01062292] Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute

9 septembre 2014

The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by (...)

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Electron shakeoff following the Β+ decay of trapped 35Ar+ ions

1er octobre 2013

The electron shakeoff of $^35$Cl atoms resulting from the $\beta$$^+$ decay of $^35$Ar$^+$ ions has been investigated using a Paul trap coupled to a recoil-ion spectrometer. The charge-state distribution of the recoiling daughter nuclei is compared to theoretical calculations accounting for (...)

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Measurement of the 6Li charge state distributions following the 6He+ beta decay

19 novembre 2012

We measure the probability of "shake-off" ionization of the daughter nucleus in the β decay of 6He+ ions confined in a transparent Paul trap. This measurement, in good agreement with theoretical calculations, allows to reduce systematic error contributions in previous β-v correlation experiments (...)

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Virtual Compton Scattering and the Generalized Polarizabilities of the Proton at Q^2=0.92 and 1.76 GeV^2

21 mai 2012

Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson Lab using the exclusive photon electroproduction reaction (e p --> e p gamma). This paper gives a detailed account of the analysis which has led to the determination of the structure functions P_LL-P_TT/epsilon (...)

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Probing the high momentum component of the deuteron at high Q^2

26 janvier 2012

The d(e,e'p) cross section at a momentum transfer of 3.5 (GeV/c)^2 was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle theta_nq and to extract missing momentum distributions for fixed (...)

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The search for the neutron electric dipole moment at the Paul Scherrer Institute

17 novembre 2011

The measurement of the neutron electric dipole moment (nEDM) constrains the contribution of CP-violating terms within both the Standard Model and its extensions. The experiment uses ultracold neutrons (UCN) stored in vacuum at room temperature. This technique provided the last (and best) limit (...)

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The search for the neutron electric dipole moment at the Paul Scherrer Institute

17 novembre 2011

The measurement of the neutron electric dipole moment (nEDM) constrains the contribution of CP-violating terms within both the Standard Model and its extensions. The experiment uses ultracold neutrons (UCN) stored in vacuum at room temperature. This technique provided the last (and best) limit (...)

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An improved measurement of the electric dipole moment of the neutron

30 mai 2011

We describe the status of the new measurement of the neutron electric dipole moment (nEDM) to be performed at the strong source of ultra-cold neutrons at the Paul Scherrer Institut. The experimental technique is based on Ramsey's method of separated oscillatory fields, applied to UCN stored in (...)

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An improved measurement of the electric dipole moment of the neutron

30 mai 2011

We describe the status of the new measurement of the neutron electric dipole moment (nEDM) to be performed at the strong source of ultra-cold neutrons at the Paul Scherrer Institut. The experimental technique is based on Ramsey's method of separated oscillatory fields, applied to UCN stored in (...)

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The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles

4 mars 2011

In the G0 experiment, performed at Jefferson Lab, the parity-violating elastic scattering of electrons from protons and quasi-elastic scattering from deuterons is measured in order to determine the neutral weak currents of the nucleon. Asymmetries as small as 1 part per million in the (...)

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The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles

4 mars 2011

In the G0 experiment, performed at Jefferson Lab, the parity-violating elastic scattering of electrons from protons and quasi-elastic scattering from deuterons is measured in order to determine the neutral weak currents of the nucleon. Asymmetries as small as 1 part per million in the (...)

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Testing isotropy of the universe using the Ramsey resonance technique on ultracold neutron spins

5 octobre 2010

Physics at the Planck scale could be revealed by looking for tiny violations of fundamental symmetries in low energy experiments. In 2008, a sensitive test of the isotropy of the Universe using has been performed with stored ultracold neutrons (UCN), this is the first clock-comparison (...)

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Testing isotropy of the universe using the Ramsey resonance technique on ultracold neutron spins

5 octobre 2010

Physics at the Planck scale could be revealed by looking for tiny violations of fundamental symmetries in low energy experiments. In 2008, a sensitive test of the isotropy of the Universe using has been performed with stored ultracold neutrons (UCN), this is the first clock-comparison (...)

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New constraints on Lorentz invariance violation from the neutron electric dipole moment

28 juin 2010

We propose an original test of Lorentz invariance in the interaction between a particle spin and an electromagnetic field and report on a first measurement using ultracold neutrons. We used a high sensitivity neutron electric dipole moment (nEDM) spectrometer and searched for a direction (...)

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[in2p3-00495497] New constraints on Lorentz invariance violation from the neutron electric dipole moment

28 juin 2010

We propose an original test of Lorentz invariance in the interaction between a particle spin and an electromagnetic field and report on a first measurement using ultracold neutrons. We used a high sensitivity neutron electric dipole moment (nEDM) spectrometer and searched for a direction (...)

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Direct experimental limit on neutron-mirror-neutron oscillations

13 janvier 2010

In case a mirror world with a copy of our ordinary particle spectrum would exist, the neutron n and its degenerate partner, the mirror neutron $\rm n'$, could potentially mix and undergo $\rm nn'$ oscillations. The interaction of an ordinary magnetic field with the ordinary neutron would lift (...)

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[in2p3-00164661] Direct experimental limit on neutron-mirror-neutron oscillations

13 janvier 2010

In case a mirror world with a copy of our ordinary particle spectrum would exist, the neutron n and its degenerate partner, the mirror neutron $\rm n'$, could potentially mix and undergo $\rm nn'$ oscillations. The interaction of an ordinary magnetic field with the ordinary neutron would lift (...)

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Additional results from the first dedicated search for neutron–mirror neutron oscillations

24 novembre 2009

The existence of a mirror world holding a copy of our ordinary particle spectrum could lead to oscillations between the neutron (n) and its mirror partner (n′). Such oscillations could manifest themselves in storage experiments with ultracold neutrons whose storage lifetime would depend on the (...)

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Additional results from the first dedicated search for neutron–mirror neutron oscillations

24 novembre 2009

The existence of a mirror world holding a copy of our ordinary particle spectrum could lead to oscillations between the neutron (n) and its mirror partner (n′). Such oscillations could manifest themselves in storage experiments with ultracold neutrons whose storage lifetime would depend on the (...)

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Towards a new measurement of the neutron electric dipole moment

24 novembre 2009

The effort towards a new measurement of the neutron electric dipole moment (nEDM) at the Paul Scherrer Institut's (PSI) new high intensity source of ultracold neutrons (UCN) is described. The experimental technique relies on Ramsey's method of separated oscillatory fields, using UCN in vacuum (...)

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Towards a new measurement of the neutron electric dipole moment

24 novembre 2009

The effort towards a new measurement of the neutron electric dipole moment (nEDM) at the Paul Scherrer Institut's (PSI) new high intensity source of ultracold neutrons (UCN) is described. The experimental technique relies on Ramsey's method of separated oscillatory fields, using UCN in vacuum (...)

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Test of Lorentz invariance with spin precession of ultracold neutrons

28 juillet 2009

A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and $^199$Hg atoms is reported. %57 No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field (...)

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[in2p3-00407985] Test of Lorentz invariance with spin precession of ultracold neutrons

28 juillet 2009

A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and $^199$Hg atoms is reported. %57 No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field (...)

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Neutron to mirror-neutron oscillations in the presence of mirror magnetic fields

27 mai 2009

We performed ultracold neutron (UCN) storage measurements to search for additional losses due to neutron (n) to mirror-neutron (n') oscillations as a function of an applied magnetic field B. In the presence of a mirror magnetic field B', UCN losses would be maximal for B = B'. We did not (...)

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[in2p3-00388703] Neutron to mirror-neutron oscillations in the presence of mirror magnetic fields

27 mai 2009

We performed ultracold neutron (UCN) storage measurements to search for additional losses due to neutron (n) to mirror-neutron (n') oscillations as a function of an applied magnetic field B. In the presence of a mirror magnetic field B', UCN losses would be maximal for B = B'. We did not (...)

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Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

2 décembre 2008

We have made the first measurements of the virtual Compton scattering (VCS) process via the H$(e,e'p)\gamma$ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the $W$-dependence at fixed $Q^2=1$ GeV$^2$, and for the $Q^2$-dependence at fixed $W$ (...)

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Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

2 décembre 2008

We have made the first measurements of the virtual Compton scattering (VCS) process via the H$(e,e'p)\gamma$ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the $W$-dependence at fixed $Q^2=1$ GeV$^2$, and for the $Q^2$-dependence at fixed $W$ (...)

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An improved neutron electric dipole moment experiment

1er juillet 2008

A new measurement of the neutron EDM, using Ramsey's method of separated oscillatory fields, is in preparation at the new high intensity source of ultra-cold neutrons (UCN) at the Paul Scherrer Institute, Villigen, Switzerland (PSI). The existence of a non-zero nEDM would violate both parity (...)

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An improved neutron electric dipole moment experiment

1er juillet 2008

A new measurement of the neutron EDM, using Ramsey's method of separated oscillatory fields, is in preparation at the new high intensity source of ultra-cold neutrons (UCN) at the Paul Scherrer Institute, Villigen, Switzerland (PSI). The existence of a non-zero nEDM would violate both parity (...)

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Towards a new measurement of the neutron electric dipole moment

29 octobre 2007

Precision measurements of particle electric dipole moments (EDMs) provide extremely sensitive means to search for non-standard mechanisms of T (or CP) violation. For the neutron EDM, the upper limit has been reduced by eight orders of magnitude in 50 years thereby excluding several CP violation (...)

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Towards a new measurement of the neutron electric dipole moment

29 octobre 2007

Precision measurements of particle electric dipole moments (EDMs) provide extremely sensitive means to search for non-standard mechanisms of T (or CP) violation. For the neutron EDM, the upper limit has been reduced by eight orders of magnitude in 50 years thereby excluding several CP violation (...)

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The neutron EDM project at PSI

2 octobre 2007

We propose to perform a new high precision measurement of the neutron Electric Dipole Moment (nEDM). Our goal is to reach an accuracy of $5\times10^-28$ e.cm or better, i.e an improvement of nearly two orders of magnitude over the present best measurement. Our experiment will use the new (...)

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The neutron EDM project at PSI

2 octobre 2007

We propose to perform a new high precision measurement of the neutron Electric Dipole Moment (nEDM). Our goal is to reach an accuracy of $5\times10^-28$ e.cm or better, i.e an improvement of nearly two orders of magnitude over the present best measurement. Our experiment will use the new (...)

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Comparison of specularly-reflecting mirrors for GRANIT

8 juin 2007

The specularity of ultracold neutron reflection was compared for different “promising” surfaces, including sapphire, silica, silica with carbon (diamond-like), and copper coatings with very small roughness. The probability of total losses of ultracold neutrons (UCN) from a specular trajectory was (...)

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Comparison of specularly-reflecting mirrors for GRANIT

8 juin 2007

The specularity of ultracold neutron reflection was compared for different “promising” surfaces, including sapphire, silica, silica with carbon (diamond-like), and copper coatings with very small roughness. The probability of total losses of ultracold neutrons (UCN) from a specular trajectory was (...)

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Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering

21 mai 2007

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 values of 0.15 and 0.25 (GeV/c)^2 with results of A_n = -4.06 +- 0.99 (stat) +- 0.63 (syst) and A_n = -4.82 +- 1.87 (stat) +- 0.98 (syst) ppm. (...)

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Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering

21 mai 2007

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 values of 0.15 and 0.25 (GeV/c)^2 with results of A_n = -4.06 +- 0.99 (stat) +- 0.63 (syst) and A_n = -4.82 +- 1.87 (stat) +- 0.98 (syst) ppm. (...)

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G$^0$ Electronics and Data Acquisition (Forward-Angle Measurements)

14 mars 2007

The G$^0$ parity-violation experiment at Jefferson Lab (Newport News, VA) is designed to determine the contribution of strange/anti-strange quark pairs to the intrinsic properties of the proton. In the forward-angle part of the experiment, the asymmetry in the cross section was measured for (...)

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G$^0$ Electronics and Data Acquisition (Forward-Angle Measurements)

14 mars 2007

The G$^0$ parity-violation experiment at Jefferson Lab (Newport News, VA) is designed to determine the contribution of strange/anti-strange quark pairs to the intrinsic properties of the proton. In the forward-angle part of the experiment, the asymmetry in the cross section was measured for (...)

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The first determination of Generalized Polarizabilities of the proton by a Virtual Compton Scattering experiment

24 décembre 2005

Absolute differential cross sections for the reaction (e+p -> e+p+gamma) have been measured at a four-momentum transfer with virtuality Q^2=0.33 GeV^2 and polarization \\epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum of the outgoing photon in the photon-proton center of (...)

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The first determination of Generalized Polarizabilities of the proton by a Virtual Compton Scattering experiment

24 décembre 2005

Absolute differential cross sections for the reaction (e+p -> e+p+gamma) have been measured at a four-momentum transfer with virtuality Q^2=0.33 GeV^2 and polarization \\epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum of the outgoing photon in the photon-proton center of (...)

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Strange-quark contributions to parity-violating asymmetries in the forward G0 electron-proton scattering experiment

23 juin 2005

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 $\leq$ Q$^2$ \leq$ 1.0 GeV$^2$. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark (...)

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Strange-quark contributions to parity-violating asymmetries in the forward G0 electron-proton scattering experiment

23 juin 2005

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 $\leq$ Q$^2$ \leq$ 1.0 GeV$^2$. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark (...)

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Experimental review of the nucleon electroweak form factors

30 mai 2005

Since more than 50 years, lots of results have been obtained on the nucleon electromagnetic form factors and their Q$^2$-dependence (up to 31 (GeV/c)$^2$ for $G_M$) through elastic electron scattering off the nucleon. This is far from being the case for the electroweak form factors which are (...)

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Experimental review of the nucleon electroweak form factors

30 mai 2005

Since more than 50 years, lots of results have been obtained on the nucleon electromagnetic form factors and their Q$^2$-dependence (up to 31 (GeV/c)$^2$ for $G_M$) through elastic electron scattering off the nucleon. This is far from being the case for the electroweak form factors which are (...)

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Quasielastic $^{3}He(e,e'p)^{2}H$ reaction at Q2=1.5 GeV2 for recoil momenta up to 1 GeV/c

26 mai 2005

We have studied the quasielastic $^3He(e,e'p)^2H$ reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The $^3He(e,e'p)^2H$ cross section was measured for missing momenta up to 1000 MeV/c, (...)

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Quasielastic $^{3}He(e,e'p)^{2}H$ reaction at Q2=1.5 GeV2 for recoil momenta up to 1 GeV/c

26 mai 2005

We have studied the quasielastic $^3He(e,e'p)^2H$ reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The $^3He(e,e'p)^2H$ cross section was measured for missing momenta up to 1000 MeV/c, (...)

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Proton elastic form factor ratios to $Q^2$=3.5 GeV$^2$ by polarization transfer

25 mai 2005

The ratio of the proton elastic electromagnetic form factors, $G_Ep/G_Mp$, was obtained by measuring $P_t$ and $P_\ell$, the transverse and longitudinal recoil proton polarization components, respectively, for the elastic $\vec e p \to e\vec p$ ~reaction in the four-momentum transfer squared (...)

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Proton elastic form factor ratios to $Q^2$=3.5 GeV$^2$ by polarization transfer

25 mai 2005

The ratio of the proton elastic electromagnetic form factors, $G_Ep/G_Mp$, was obtained by measuring $P_t$ and $P_\ell$, the transverse and longitudinal recoil proton polarization components, respectively, for the elastic $\vec e p \to e\vec p$ ~reaction in the four-momentum transfer squared (...)

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Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta

14 mars 2005

Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q = 1502 MeV/c and omega = 840 MeV, respectively, for missing momenta p_m up to 1 GeV/c and missing energies in the continuum (...)

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Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta

14 mars 2005

Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q = 1502 MeV/c and omega = 840 MeV, respectively, for missing momenta p_m up to 1 GeV/c and missing energies in the continuum (...)

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CARTOGRAPHIE MAGNETIQUE DES QUADRIPOLES DES SPECTROMETRES A HAUTE RESOLUTION DU THOMAS JEFFERSON NATIONAL ACCELERATOR LABORATORY, HALL A. (Le Projet Q.M.M : Quadrupole Magnetic Measurement)

17 décembre 2004

Cette thèse décrit les mesures magnétiques réalisées sur les quadripoles supraconducteurs équipant les spectromètres à haute résolution (HRS) de TJNAF, Hall A (USA), caractérisés par une résolution sigma p/p= 10 -4 pour p <4 GeV.c-1. Une méthode originale basée sur une sonde tournante multibobines a (...)

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CARTOGRAPHIE MAGNETIQUE DES QUADRIPOLES DES SPECTROMETRES A HAUTE RESOLUTION DU THOMAS JEFFERSON NATIONAL ACCELERATOR LABORATORY, HALL A. (Le Projet Q.M.M : Quadrupole Magnetic Measurement)

17 décembre 2004

Cette thèse décrit les mesures magnétiques réalisées sur les quadripoles supraconducteurs équipant les spectromètres à haute résolution (HRS) de TJNAF, Hall A (USA), caractérisés par une résolution sigma p/p= 10 -4 pour p <4 GeV.c-1. Une méthode originale basée sur une sonde tournante multibobines a (...)

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The dynamics of the quasielastic $^{16}O$(e,e'p) reaction at $Q^2$ $\approx$ 0.8 (GeV/c)$^2$

1er décembre 2004

The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the 16O(e,e'p) reaction in quasielastic, constant (q,w) kinematics at Q^2 ~ 0.8 (GeV/c)^2, q ~ 1 GeV/c, and w ~ 445 MeV. Use of a self-calibrating, self-normalizing, thin-film (...)

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The dynamics of the quasielastic $^{16}O$(e,e'p) reaction at $Q^2$ $\approx$ 0.8 (GeV/c)$^2$

1er décembre 2004

The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the 16O(e,e'p) reaction in quasielastic, constant (q,w) kinematics at Q^2 ~ 0.8 (GeV/c)^2, q ~ 1 GeV/c, and w ~ 445 MeV. Use of a self-calibrating, self-normalizing, thin-film (...)

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Measurement of the generalized polarizabilities of the proton in virtual compton scattering at $Q^2$ = 0.92 and 1.76 Gev$^2$

1er décembre 2004

We report a Virtual Compton Scattering study of the proton in Hall A at the Thomas Jefferson National Accelerator Facility at low CM energies. We have determined the structure functions $P_LL-P_TT/\epsilon$ and $P_LT$, and the electric and magnetic Generalized Polarizabilities (GP) (...)

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Measurement of the generalized polarizabilities of the proton in virtual compton scattering at $Q^2$ = 0.92 and 1.76 Gev$^2$

1er décembre 2004

We report a Virtual Compton Scattering study of the proton in Hall A at the Thomas Jefferson National Accelerator Facility at low CM energies. We have determined the structure functions $P_LL-P_TT/\epsilon$ and $P_LT$, and the electric and magnetic Generalized Polarizabilities (GP) (...)

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Virtual compton scattering in the resonance region up to the deep inelastic region at backward angles and momentum transfer squared of $Q^2$ = 1.0 $GeV^2$

5 mai 2004

We have made the first measurements of the virtual Compton scattering process via the e p -> e p gamma exclusive reaction at Q**2 = 1 GeV**2 in the nucleon resonance region. The cross section is obtained at center of mass (CM) backward angle, theta_gamma_gamma*, in a range of total (gamma* (...)

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Virtual compton scattering in the resonance region up to the deep inelastic region at backward angles and momentum transfer squared of $Q^2$ = 1.0 $GeV^2$

5 mai 2004

We have made the first measurements of the virtual Compton scattering process via the e p -> e p gamma exclusive reaction at Q**2 = 1 GeV**2 in the nucleon resonance region. The cross section is obtained at center of mass (CM) backward angle, theta_gamma_gamma*, in a range of total (gamma* (...)

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Backward electroproduction of $\pi^0$ mesons on protons in the region of nucleon resonances at four momentum transfer squared $Q^2 = 1.0 GeV^2$

5 mai 2004

Exclusive electroproduction of pi0 mesons on protons in the backward hemisphere has been studied at Q2=1.0 GeV2 by detecting protons in the forward direction in coincidence with scattered electrons from the 4 GeV electron beam in Jefferson Lab's Hall A. The data span the range of the total (...)

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Backward electroproduction of $\pi^0$ mesons on protons in the region of nucleon resonances at four momentum transfer squared $Q^2 = 1.0 GeV^2$

5 mai 2004

Exclusive electroproduction of pi0 mesons on protons in the backward hemisphere has been studied at Q2=1.0 GeV2 by detecting protons in the forward direction in coincidence with scattered electrons from the 4 GeV electron beam in Jefferson Lab's Hall A. The data span the range of the total (...)

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Parity violating electron deuteron scattering and the proton's neutral weak axial vector form-factor

6 avril 2004

We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2= 0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive (...)

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Parity violating electron deuteron scattering and the proton's neutral weak axial vector form-factor

6 avril 2004

We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2= 0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive (...)

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Dynamics of the $^{16}$O(e,e'p) cross section at high missing energies

25 juin 2001

We measured the cross section and response functions (R_L, R_T, and R_LT) for the 16O(e,e'p) reaction in quasielastic kinematics for missing energies 25 <= E_miss <= 120 MeV at various missing momenta P_miss <= 340 MeV/c. For 25 < E_miss < 50 MeV and 1s1/2-state. At (...)

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Dynamics of the $^{16}$O(e,e'p) cross section at high missing energies

25 juin 2001

We measured the cross section and response functions (R_L, R_T, and R_LT) for the 16O(e,e'p) reaction in quasielastic kinematics for missing energies 25 <= E_miss <= 120 MeV at various missing momenta P_miss <= 340 MeV/c. For 25 < E_miss < 50 MeV and 1s1/2-state. At (...)

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Polarization transfer in the ${16}O$ ($\vec{e},e'\vec{p}$) $^{15}$N reaction.

10 octobre 2000

The first (e,e'p) polarization transfer measurements on a nucleus heavier than deuterium have been carried out at Jefferson Laboratory. Transverse and longitudinal components of the polarization of protons ejected in the reaction 16O(e,e'p) were measured in quasielastic perpendicular kinematics (...)

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Polarization transfer in the ${16}O$ ($\vec{e},e'\vec{p}$) $^{15}$N reaction.

10 octobre 2000

The first (e,e'p) polarization transfer measurements on a nucleus heavier than deuterium have been carried out at Jefferson Laboratory. Transverse and longitudinal components of the polarization of protons ejected in the reaction 16O(e,e'p) were measured in quasielastic perpendicular kinematics (...)

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Virtual Compton Scattering and polarizabilities

10 octobre 2000

Virtual Compton Scattering (VCS) of the proton below pion threshold allows access to generalized polarizabilities of the proton. These observables measure the response of the nucleon to low energy electromagnetic field perturbations. This paper presents a comparison with Real Compton Scattering (...)

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Virtual Compton Scattering and polarizabilities

10 octobre 2000

Virtual Compton Scattering (VCS) of the proton below pion threshold allows access to generalized polarizabilities of the proton. These observables measure the response of the nucleon to low energy electromagnetic field perturbations. This paper presents a comparison with Real Compton Scattering (...)

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$G_{E_p}/G_{M_p}$ ratio by polarization transfer in $\vec{e}p\rightarrow e\vec{p}$

15 février 2000

The ratio of the proton's elastic electromagnetic form factors was obtained by measuring the transverse and longitudinal polarizations of recoiling protons from the elastic scattering of polarized electrons with unpolarized protons. The ratio of the electric to magnetic form factor is (...)

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$G_{E_p}/G_{M_p}$ ratio by polarization transfer in $\vec{e}p\rightarrow e\vec{p}$

15 février 2000

The ratio of the proton's elastic electromagnetic form factors was obtained by measuring the transverse and longitudinal polarizations of recoiling protons from the elastic scattering of polarized electrons with unpolarized protons. The ratio of the electric to magnetic form factor is (...)

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Measurements of the deuteron elastic structure function $A(Q^2)$ for $0.7\leq Q^2\leq 6.0$ (GeV/c)$^2$ at Jefferson Laboratory

10 mai 1999

The deuteron elastic structure function A(Q^2) has been extracted in the Q^2 range 0.7 to 6.0 (GeV/c)^2 from cross section measurements of elastic electron-deuteron scattering in coincidence using the Hall A Facility of Jefferson Laboratory. The data are compared to theoretical models based on (...)

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Measurement of the neutral weak form-factors of the proton

10 mai 1999

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point (theta_lab = 12.3 degrees and Q^2=0.48 (GeV/c)^2) is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange (...)

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