1,329 research outputs found
Collaboration in electronic resource provision in university libraries: SHEDL, a Scottish case study
This case study examines the growth of collaboration among Scottish higher education institutions. Following a summary of the work of the Scottish Confederation of University and Research Libraries (SCURL), more detailed information is provided on collaboration in the fields of acquisition, licensing, selection, and purchasing. Some of the UK background is outlined, relating to NESLi2 in particular, in order to illuminate the options within Scotland. The origins of negotiations on electronic resource provision within Scotland are described, drawing on developments in other countries including Ireland and Scandinavia. After initial setbacks, the implementation of the Scottish Higher Education Digital Library (SHEDL) from 2007 to 2009 is detailed. Current benefits arising from SHEDL are explained, and some possible future developments are discussed
QCD and Yukawa corrections to single-top-quark production via q qbar -> t bbar
We calculate the O(alpha_s) and O(alpha_W m_t^2/M_W^2) corrections to the
production of a single top quark via the weak process q qbar -> t bbar at the
Fermilab Tevatron and the CERN Large Hadron Collider. An accurate calculation
of the cross section is necessary in order to extract |V_tb| from experiment.Comment: LaTeX, 13 pages, replaced with version to appear in Phys. Rev.
Window on Higgs Boson: Fourth Generation Decays Revisited
Direct and indirect searches of the Higgs boson suggest that 113 GeV
170 GeV is likely. With the LEP era over and the
Tevatron Run II search via arduous, we revisit a case where
or jets could arise via strong pair
production. In contrast to 10 years ago, the tight electroweak constraint on
-- (hence --) splitting reduces FCNC
, rates, making naturally competitive.
Such a "cocktail solution" is precisely the mix that could evade the CDF search
for , and the may well be lurking below the top. In
light of the Higgs program, this two-in-one strategy should be pursued.Comment: 4 pages, RevTex, 4 eps figures, One more figure, version to be
published in Phys. Rev.
Yukawa Corrections to Top Quark Production at the LHC in Two- Higgs-Doublet Models
The O(alpha m_t^2/m_W^2) corrections to top quark pair production by
gluon-gluon fusion at the LHC are calculated in two-Higgs-doublet models. We
find that the correction to the cross-section can exceed about -10% for certain
parameter values.Comment: 16-page text in LaTex. uuencoded file for Fig.1-6 will be sent
separatel
The Reach of CERN LEP2 and Fermilab Tevatron Upgrades for Higgs Bosons in Supersymmetric Models
Luminosity upgrades of the Fermilab Tevatron pbar-p collider have been shown
to allow experimental detection of a Standard Model (SM) Higgs boson up to
GeV via events. This limit
nearly saturates the parameter space for many models of weak scale
supersymmetry (SUSY) with a minimal particle content. It is therefore
interesting to examine the SUSY Higgs reach of future Tevatron experiments.
Contours are presented of Higgs boson reach for CERN LEP2 and Tevatron
luminosity upgrades for three models of weak scale SUSY: the Minimal
Supersymmetric Standard Model (MSSM), the minimal Supergravity model (mSUGRA)
and a simple Gauge Mediated SUSY Breaking Model (GMSB). In each case we find a
substantial gain in reach at the Tevatron with integrated luminosity increasing
from 10 fb^{-1} to 25-30 fb^{-1}. With the larger integrated luminosity, a
Higgs search at the Tevatron should be able to probe essentially the entire
parameter space of these models. While a discovery would be very exciting, a
negative result would severely constrain our ideas about how weak scale
supersymmetry is realized.Comment: 12 pages + 7 figures. Uses REVTEX and epsf macros. Several references
added, stated value of A-parameters corrected, note added reguarding sgn(mu)
dependence in MSSM case. To appear in Physical Review
Radiative Higgs Boson Decays H\to f\bar{f}\gamma Beyond the Standard Model
Neutral Higgs boson radiative decays of the form h_0, H, A \to
f\bar{f}\gamma, in the light fermion limit $m_f->0, are calculated in the two
Higgs doublet model at one-loop level. Comparisons with the calculation within
the standard model are given, which indicates that these two models are
distinguishable in the decay mode fermion-antifermion -photon. Our results show
that the concerned process may stand as an implement to identify the Higgs
belongings in case there is a intermediate mass Higgs detected.Comment: 13 pages in Revtex, version to appear in Phys. Rev.
A Higgs or Not a Higgs? What to Do if You Discover a New Scalar Particle
We show how to systematically analyze what may be inferred should a new
scalar particle be discovered in collider experiments. Our approach is
systematic in the sense that we perform the analysis in a manner which
minimizes apriori theoretical assumptions as to the nature of the scalar
particle. For instance, we do not immediately make the common assumption that a
new scalar particle is a Higgs boson, and so must interact with a strength
proportional to the mass of the particles with which it couples. We show how to
compare different observables, and so to develop a decision tree from which the
nature of the new particle may be discerned. We define several categories of
models, which summarize the kinds of distinctions which the first experiments
can make.Comment: 66 pages, 14 figures, version to appear in International Journal of
Mod. Phys.
Ion acceleration in plasmas emerging from a helicon-heated magnetic-mirror device
Using laser-induced fluorescence, measurements have been made of metastable argon-ion, Ar{sup +}*(3d{sup 4} f{sub 7/2}), velocity distributions on the major axis of an axisymmetric magnetic-mirror device whose plasma is sustained by helicon wave absorption. Within the mirror, these ions have sub-eV temperature and, at most, a subthermal axial drift. In the region outside the mirror coils, conditions are found where these ions have a field-parallel velocity above the acoustic speed, to an axial energy of {approx}30 eV, while the field-parallel ion temperature remains low. The supersonic Ar{sup +}*(3d{sup 4} f{sub 7/2}) are accelerated to one-third of their final energy within a short region in the plasma column, {le}1 cm, and continue to accelerate over the next 5 cm. Neutral gas density strongly affects the supersonic Ar{sup +}*(3d{sup 4} f{sub 7/2}) density
Detecting a light Higgs boson at the Fermilab Tevatron through enhanced decays to photon pairs
We analyze the prospects of the Tevatron for finding a Higgs boson in the two
photon decay mode. We conclude that the Standard Model (SM) Higgs boson will
likely not be discovered in this mode. However, we motivate several theories
beyond the SM, including the MSSM, that predict a Higgs boson with enhanced
branching fractions into photons, and calculate the luminosity needed to
discover a general Higgs boson at the Tevatron by a two-photon invariant mass
peak at large transverse momentum. We find that a high luminosity Tevatron will
play a significant role in discovering or constraining these theories.Comment: 20 pages, latex, 5 figure
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