201 research outputs found
A ‘quiet revolution’? The impact of Training Schools on initial teacher training partnerships
This paper discusses the impact on initial teacher training of a new policy initiative in England: the introduction of Training Schools. First, the Training School project is set in context by exploring the evolution of a partnership approach to initial teacher training in England. Ways in which Training Schools represent a break with established practice are considered together with their implications for the dominant mode of partnership led by higher education institutions (HEIs). The capacity of Training Schools to achieve their own policy objectives is examined, especially their efficacy as a strategy for managing innovation and the dissemination of innovation. The paper
ends by focusing on a particular Training School project which has adopted an unusual approach to its work and enquires whether this alternative approach could offer a more profitable way forward. During the course of the paper, five different models of partnership are considered:
collaborative, complementary, HEI-led, school-led and partnership within a partnership
Photoproduction of phi(1020) mesons on the proton at large momentum transfer
The cross section for meson photoproduction on the proton has been
measured for the first time up to a four-momentum transfer -t = 4 GeV^2, using
the CLAS detector at the Thomas Jefferson National Accelerator Facility. At low
four-momentum transfer, the differential cross section is well described by
Pomeron exchange. At large four-momentum transfer, above -t = 1.8 GeV^2, the
data support a model where the Pomeron is resolved into its simplest component,
two gluons, which may couple to any quark in the proton and in the .Comment: 5 pages; 7 figure
Measurement of Inclusive Spin Structure Functions of the Deuteron
We report the results of a new measurement of spin structure functions of the
deuteron in the region of moderate momentum transfer ( = 0.27 -- 1.3
(GeV/c)) and final hadronic state mass in the nucleon resonance region (
= 1.08 -- 2.0 GeV). We scattered a 2.5 GeV polarized continuous electron beam
at Jefferson Lab off a dynamically polarized cryogenic solid state target
(ND) and detected the scattered electrons with the CEBAF Large
Acceptance Spectrometer (CLAS). From our data, we extract the longitudinal
double spin asymmetry and the spin structure function . Our
data are generally in reasonable agreement with existing data from SLAC where
they overlap, and they represent a substantial improvement in statistical
precision. We compare our results with expectations for resonance asymmetries
and extrapolated deep inelastic scaling results. Finally, we evaluate the first
moment of the structure function and study its approach to both the
deep inelastic limit at large and to the Gerasimov-Drell-Hearn sum rule
at the real photon limit (). We find that the first moment varies
rapidly in the range of our experiment and crosses zero at between
0.5 and 0.8 (GeV/c), indicating the importance of the resonance at
these momentum transfers.Comment: 13 pages, 8 figures, ReVTeX 4, final version as accepted by Phys.
Rev.
eta-prime photoproduction on the proton for photon energies from 1.527 to 2.227 GeV
Differential cross sections for the reaction gamma p -> eta-prime p have been
measured with the CLAS spectrometer and a tagged photon beam with energies from
1.527 to 2.227 GeV. The results reported here possess much greater accuracy
than previous measurements. Analyses of these data indicate for the first time
the coupling of the etaprime N channel to both the S_11(1535) and P_11(1710)
resonances, known to couple strongly to the eta N channel in photoproduction on
the proton, and the importance of j=3/2 resonances in the process.Comment: 6 pages, 3 figure
First Measurement of Transferred Polarization in the Exclusive e p --> e' K+ Lambda Reaction
The first measurements of the transferred polarization for the exclusive ep
--> e'K+ Lambda reaction have been performed in Hall B at the Thomas Jefferson
National Accelerator Facility using the CLAS spectrometer. A 2.567 GeV electron
beam was used to measure the hyperon polarization over a range of Q2 from 0.3
to 1.5 (GeV/c)2, W from 1.6 to 2.15 GeV, and over the full center-of-mass
angular range of the K+ meson. Comparison with predictions of hadrodynamic
models indicates strong sensitivity to the underlying resonance contributions.
A non-relativistic quark model interpretation of our data suggests that the
s-sbar quark pair is produced with spins predominantly anti-aligned.
Implications for the validity of the widely used 3P0 quark-pair creation
operator are discussed.Comment: 6 pages, 4 figure
Onset of asymptotic scaling in deuteron photodisintegration
We investigate the transition from the nucleon-meson to quark-gluon
description of the strong interaction using the photon energy dependence of the
differential cross section for photon energies above 0.5 GeV and
center-of-mass proton angles between and . A possible
signature for this transition is the onset of cross section scaling
with the total energy squared, , at some proton transverse momentum, .
The results show that the scaling has been reached for proton transverse
momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime
is reached above this momentum.Comment: Accepted by PRL; 5 pages, 2 figure
Complete measurement of three-body photodisintegration of 3He for photon energies between 0.35 and 1.55 GeV
The three-body photodisintegration of 3He has been measured with the CLAS
detector at Jefferson Lab, using tagged photons of energies between 0.35 GeV
and 1.55 GeV. The large acceptance of the spectrometer allowed us for the first
time to cover a wide momentum and angular range for the two outgoing protons.
Three kinematic regions dominated by either two- or three-body contributions
have been distinguished and analyzed. The measured cross sections have been
compared with results of a theoretical model, which, in certain kinematic
ranges, have been found to be in reasonable agreement with the data.Comment: 22 pages, 25 eps figures, 2 tables, submitted to PRC. Modifications:
removed 2 figures, improvements on others, a few minor modifications to the
tex
Observation of exclusive DVCS in polarized electron beam asymmetry measurements
We report the first results of the beam spin asymmetry measured in the
reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry
with a sin(phi) modulation is observed, as predicted for the interference term
of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The
amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and
leading-twist pQCD, the alpha is directly proportional to the imaginary part of
the DVCS amplitude.Comment: 6 pages, 5 figure
Q^2 Dependence of the S_{11}(1535) Photocoupling and Evidence for a P-wave resonance in eta electroproduction
New cross sections for the reaction are reported for total
center of mass energy =1.5--2.3 GeV and invariant squared momentum transfer
=0.13--3.3 GeV. This large kinematic range allows extraction of new
information about response functions, photocouplings, and coupling
strengths of baryon resonances. A sharp structure is seen at 1.7 GeV.
The shape of the differential cross section is indicative of the presence of a
-wave resonance that persists to high . Improved values are derived for
the photon coupling amplitude for the (1535) resonance. The new data
greatly expands the range covered and an interpretation of all data with
a consistent parameterization is provided.Comment: 31 pages, 9 figure
A Precise Measurement of the Neutron Magnetic Form Factor GMn in the Few-GeV2 Region
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. The kinematic coverage of the
measurement is continuous from Q2=1 GeV2 to 4.8 GeV2. High precision was
achieved by employing a ratio technique in which many uncertainties cancel, and
by a simultaneous in-situ calibration of the neutron detection efficiency, the
largest correction to the data. Neutrons were detected using the CLAS
electromagnetic calorimeters and the time-of-flight scintillators. Data were
taken at two different electron beam energies, allowing up to four
semi-independent measurements of GMn to be made at each value of Q2. The dipole
parameterization is found to provide a good description of the data over the
measured Q2 range.Comment: 14 pages, 5 figures, revtex4, submitted to Physical Review Letters,
Revised version has changes recommended by journal referee
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