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Is a standalone IL course useful?
Most Higher Education institutions are involved in the creation of online materials to support their students' information literacy skills development – which is labour intensive, and inevitably results in a great deal of duplication of effort across the sector. A recent project, run jointly by SCONUL's Advisory Committee on Information Literacy and The Open University, addressed whether it is possible to create a generic information literacy course that can be delivered anywhere. The OU's standalone module, MOSAIC, which has been running for the last three years with positive feedback from students, provided an ideal starting point for the investigation
A new type of temperature driven reorientation transition in magnetic thin films
We present a new type of temperature driven spin reorientation transition
(SRT) in thin films. It can occur when the lattice and the shape anisotropy
favor different easy directions of the magnetization. Due to different
temperature dependencies of the two contributions the effective anisotropy may
change its sign and thus the direction of the magnetization as a function of
temperature may change. Contrary to the well-known reorientation transition
caused by competing surface and bulk anisotropy contributions the reorientation
that we discuss is also found in film systems with a uniform lattice
anisotropy. The results of our theoretical model study may have experimental
relevance for film systems with positive lattice anisotropy, as e.g. thin iron
films grown on copper.Comment: 7 pages, 4 figures, accepted for publication in EPJ
The Ideal Mixing Departure in Vector Meson Physics
In this work we study the departure for the ideal mixing angle
in the frame of the Nambu-Jona-Lasinio model. We have shown that in that
context, the flavour symmetry breaking is unable to produce the shifting in the
mixing angle. We introduce a nonet symmetry breaking in the neutral vector
sector to regulate the non-strange content of the meson. The phenomenon
is well reproduced by our proposal.Comment: 12 pages incl. 1 figur
The running of the electromagnetic coupling alpha in small-angle Bhabha scattering
A method to determine the running of alpha from a measurement of small-angle
Bhabha scattering is proposed and worked out. The method is suited to high
statistics experiments at e+e- colliders, which are equipped with luminometers
in the appropriate angular region. A new simulation code predicting small-angle
Bhabha scattering is also presentedComment: 15 pages, 3 Postscript figure
Numerical evidence for relevance of disorder in a Poland-Scheraga DNA denaturation model with self-avoidance: Scaling behavior of average quantities
We study numerically the effect of sequence heterogeneity on the
thermodynamic properties of a Poland-Scheraga model for DNA denaturation taking
into account self-avoidance, i.e. with exponent c_p=2.15 for the loop length
probability distribution. In complement to previous on-lattice Monte Carlo like
studies, we consider here off-lattice numerical calculations for large sequence
lengths, relying on efficient algorithmic methods. We investigate finite size
effects with the definition of an appropriate intrinsic length scale x,
depending on the parameters of the model. Based on the occurrence of large
enough rare regions, for a given sequence length N, this study provides a
qualitative picture for the finite size behavior, suggesting that the effect of
disorder could be sensed only with sequence lengths diverging exponentially
with x. We further look in detail at average quantities for the particular case
x=1.3, ensuring through this parameter choice the correspondence between the
off-lattice and the on-lattice studies. Taken together, the various results can
be cast in a coherent picture with a crossover between a nearly pure system
like behavior for small sizes N < 1000, as observed in the on-lattice
simulations, and the apparent asymptotic behavior indicative of disorder
relevance, with an (average) correlation length exponent \nu_r >= 2/d (=2).Comment: Latex, 33 pages with 15 postscript figure
On kaonic hydrogen. Quantum field theoretic and relativistic covariant approach
We study kaonic hydrogen, the bound K^-p state A_(Kp). Within a quantum field
theoretic and relativistic covariant approach we derive the energy level
displacement of the ground state of kaonic hydrogen in terms of the amplitude
of K^-p scattering for arbitrary relative momenta. The amplitude of low-energy
K^-p scattering near threshold is defined by the contributions of three
resonances Lambda(1405), Lambda(1800) and Sigma^0(1750) and a smooth elastic
background. The amplitudes of inelastic channels of low-energy K^-p scattering
fit experimental data on near threshold behaviour of the cross sections and the
experimental data by the DEAR Collaboration. We use the soft-pion technique
(leading order in Chiral Perturbation Theory) for the calculation of the
partial width of the radiative decay of pionic hydrogen A_(pi p) -> n + gamma
and the Panofsky ratio. The theoretical prediction for the Panofsky ratio
agrees well with experimental data. We apply the soft-kaon technique (leading
order in Chiral Perturbation Theory) to the calculation of the partial widths
of radiative decays of kaonic hydrogen A_(Kp) -> Lambda^0 + gamma and A_(Kp) ->
Sigma^0 + gamma. We show that the contribution of these decays to the width of
the energy level of the ground state of kaonic hydrogen is less than 1%.Comment: 33 pages, 1 figure, latex, References are adde
Probing New Physics from Top-charm Associated Productions at Linear Colliders
The top-charm associated productions via , and collisions at linear colliders, which are extremely suppressed in the
Standard Model (SM), could be significantly enhanced in some extensions of the
SM. In this article we calculate the full contribution of the topcolor-assisted
technicolor (TC2) to these productions and then compare the results with the
existing predictions of the SM, the general two-Higgs-doublet model and the
Minimal Supersymmetric Model. We find that the TC2 model predicts much larger
production rates than other models and the largest-rate channel is , which exceeds 10 fb for a large part of the parameter
space. From the analysis of the observability of such productions at the future
linear colliders, we find that the predictions of the TC2 model can reach the
observable level for a large part of the parameter space while the predictions
of other models are hardly accessible.Comment: discussions added (version in Eur. Phys. J. C
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at = 2.76 TeV
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/388
Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at TeV
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb
collisions at = 2.76 TeV have been measured by the ALICE
Collaboration at the LHC. The data are presented for central and peripheral
collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross
section. The measured charged particle spectra in and GeV/ are compared to the expectation in pp collisions at the same
, scaled by the number of underlying nucleon-nucleon
collisions. The comparison is expressed in terms of the nuclear modification
factor . The result indicates only weak medium effects ( 0.7) in peripheral collisions. In central collisions,
reaches a minimum of about 0.14 at -7GeV/ and increases
significantly at larger . The measured suppression of high- particles is stronger than that observed at lower collision energies,
indicating that a very dense medium is formed in central Pb-Pb collisions at
the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98
Reconclining phi radiative decays with other data for a0(980), fo(980), pi-pi -> KK and pi-pi -> eta-eta
Data for phi -> gamma (eta-pizero) are analysed using the KK loop model and
compared with parameters of a0(980) derived from Crystal Barrel data. The
eta-pi mass spectrum agrees closely and the absolute normalisation lies just
within errors. However, BES parameters for fo(980) predict a normalisation for
phi -> gamma (pizero-pizero) at least a factor 2 lower than is observed. This
discrepancy may be eliminated by including constructive interference between
fo(980) and sigma. The magnitude required for sigma -> KK is consistent with
data on pi-pi -> KK. A dispersion relation analysis by Buttiker, Descotes-Genon
and Moussallam of pi-pi -> KK leads to a similar conclusion. Data on pi-pi ->
eta-eta also require decays of sigma to eta-eta. Four sets of pi-pi -> KK data
all require a small but definite fo(1370) signal.Comment: 21 pages, 11 figures, Small rearrangement of reference
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