121021036
G**p(E) / G**p(M) for bound protons: first results for O-16 with the recoil polarization technique
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 at a Q^2 of 0.8 (GeV/c)^2. The data are in good agreement with state of the art calculations, but do not exclude possible changes in the ratio of the electric to magnetic form factors of the nucleon in the nuclear medium at the level of recent theoretical predictions.
121171727
Electromagnetic structure of the helium isotopes
The elastic-electron scattering cross sections from $^{3}\mathrm{He}$ and $^{4}\mathrm{He}$ have been measured at incident electron energies between 170 and 750 MeV. Cross sections were separated into their longitudinal (charge) and transverse (magnetic) contributions using the Rosenbluth formula. Values of the $^{3}\mathrm{He}$ charge form factor have been extracted to ${q}^{2}=20$ ${\mathrm{fm}}^{\ensuremath{-}2}$ and for the $^{3}\mathrm{He}$ magnetic form factor to ${q}^{2}=16$ ${\mathrm{fm}}^{\ensuremath{-}2}$. The $^{4}\mathrm{He}$ form factor has been determined up to 6.2 ${\mathrm{fm}}^{\ensuremath{-}2}$. Densities for the charge and magnetization have been deduced from phenomenological models used in a phase-shift solution of the Dirac equation. A model-independent determination of the nuclear densities has been performed in order to obtain realistic errors on the extracted distributions. After unfolding the nucleon size from the distributions the point density is shown to have a significant central depression for a radius 0.8 fm for both $^{3}\mathrm{He}$ and $^{4}\mathrm{He}$. Comparison of the form factors is made with Faddeev and variational three-body calculations that use realistic two-body $\mathrm{NN}$ interactions. The influence of off-shell effects, three-body forces, meson-exchange corrections, and short-range correlations are discussed. At present no theoretical calculation that uses input derived entirely from nucleon-nucleon scattering is able to reproduce the experimental data.
125095013
Measurements of the nucleon spin structure at SLAC in end station A.
121139038
CEBAF — a high energy, high duty factor electron accelerator for nuclear physics☆
Abstract The Nuclear Science Advisory Committee has recommended the construction of the Continuous Electron Beam Accelerator Facility (CEBAF) as proposed by the Southeastern Universities Research Association (SURA), a consortium of more than thirty institutions in the southeastern United States. The accelerator will be capable of delivering intense (Iave > 100 μA), quasi-continuous (duty Factor > 90%) beams of electrons with energies up to 4.8 GeV. Short (1.2 μs), intense (Ipk = 200 mA) pulses of electrons will be accelerated by passing twice through a conventional pulsed linac. The pulses then will be injected into and stored in a pulse stretcher ring, the circumference of which is close to the length of the electron pulse. During the period between pulses (1ms) the stored electrons will be extracted to yield a high duty factor beam. Delivery of arbitrarily polarized beams will be possible. Experimental facilities will include three end stations. Two will be used for experiments utilizing the primary electron beam; the third will serve as a tagged photon facility.
119997319
Scattering of Fast Electrons by Oriented Ho^{165} Nuclei
134540303
ELECTROEXCITATION OF DELTA IN NUCLEI
197461694
Evidence for the decay $X(3872)\rightarrow\psi(2S)\gamma$
Evidence for the decay mode $X(3872)\rightarrow\psi(2S)\gamma$ in $B^+\rightarrow X(3872)K^+$ decays is found with a significance of 4.4 standard deviations. The analysis is based on a data sample of proton-proton collisions, corresponding to an integrated luminosity of 3fb$^{-1}$ collected with the LHCb detector, at centre-of-mass energies of 7 and 8TeV. The ratio of the branching fraction of the $X(3872)\to\psi(2S)\gamma$ decay to that of the $X(3872)\rightarrow J/\psi \gamma$ decay is measured to be $$ \frac{Br(X(3872)\rightarrow\psi(2S)\gamma)}{Br(X(3872)\rightarrow J/\psi\gamma)} = 2.46\pm0.64\pm0.29, %\pm0.06,$$ where the first uncertainty is statistical and the second is systematic. The measured value agrees with expectations for a pure charmonium interpretation of the $X(3872)$ state and a mixture of charmonium and molecular interpretations. However, it does not support a pure $D\bar{D}^{*}$ molecular interpretation of the $X(3872)$state.
21928269
Large Dynamic Range Beam Profile Measurement in a High Background Environment
Beam profile measurements using a scanning target and loss monitor in the Fermilab Main Ring extraction channel have long proved their usefulness as a diagnostic method in analyzing extraction problems. To extend these measurements to a sensitivity greater than in the present system a different technique has been employed. A simple three element particle telescope viewing the scanning target allows a sensitive measurement of the tail on the edges of the beam profiles as well as the relative particle densities of the extracted beam and the circulating beam in the Main Ring. Both these regions are of significant interest in understanding extraction losses. The details of the profile measurement technique, some results using the telescope and possible methods of improving the measurements are discussed.
118521922
Implications of LHCb measurements and future prospects
During 2011 the LHCb experiment at CERN collected 1.0 fb−1 of $\sqrt{s} = 7\mbox{~TeV}$pp collisions. Due to the large heavy quark production cross-sections, these data provide unprecedented samples of heavy flavoured hadrons. The first results from LHCb have made a significant impact on the flavour physics landscape and have definitively proved the concept of a dedicated experiment in the forward region at a hadron collider. This document discusses the implications of these first measurements on classes of extensions to the Standard Model, bearing in mind the interplay with the results of searches for on-shell production of new particles at ATLAS and CMS. The physics potential of an upgrade to the LHCb detector, which would allow an order of magnitude more data to be collected, is emphasised.
119962020
A Study of the Vertex in Witten's String Field Theory
Abstract We consider Witten's formulation of the interacting open bosonic string field theory. In particular, we study the Fock space representation of the vertex, including the fields associated with the bosonized two-dimensional ghost oscillators. We calculate the vertex using conformal mapping techniques, and also via a decomposition of the constraints implied by the string overlap. The conformal mapping takes the overlap world sheet to an anticone, where the Neumann function may be found. We show how this is related to the mappings with branch cut singularities, which take this world sheet to the upper half plane.
54960779
Measurement of the resonant and CP components in $\overline{B}^0\to J/\psi \pi^+\pi^-$ decays
The resonant structure of the reaction $\overline{B}^0\rightarrow J/\psi \pi^+\pi^-$ is studied using data from 3 fb$^{-1}$ of integrated luminosity collected by the LHCb experiment, one-third at 7 Tev center-of-mass energy and the remainder at 8 Tev. The invariant mass of the $\pi^+\pi^-$ pair and three decay angular distributions are used to determine the fractions of the resonant and non-resonant components. Six interfering $\pi^+\pi^-$ states: $\rho(770)$, $f_0(500)$, $f_2(1270)$, $\rho(1450)$, $\omega(782)$ and $\rho(1700)$ are required to give a good description of invariant mass spectra and decay angular distributions. The positive and negative CP fractions of each of the resonant final states are determined. The $f_0(980)$ meson is not seen and the upper limit on its presence, compared with the observed $f_0(500)$ rate, is inconsistent with a model of tetraquark substructure for these scalar mesons at the eight standard deviation level. In the $q\overline{q}$ model, the absolute value of the mixing angle between the $f_0(980)$ and the $f_0(500)$ scalar mesons is limited to be less than $17^{\circ}$ at 90% confidence level.