443 research outputs found
The Minimally Tuned Minimal Supersymmetric Standard Model
The regions in the Minimal Supersymmetric Standard Model with the minimal
amount of fine-tuning of electroweak symmetry breaking are presented for
general messenger scale. No a priori relations among the soft supersymmetry
breaking parameters are assumed and fine-tuning is minimized with respect to
all the important parameters which affect electroweak symmetry breaking. The
superpartner spectra in the minimally tuned region of parameter space are quite
distinctive with large stop mixing at the low scale and negative squark soft
masses at the high scale. The minimal amount of tuning increases enormously for
a Higgs mass beyond roughly 120 GeV.Comment: 38 pages, including 2 appendices, 8 figure
Supersymmetry and the LHC Inverse Problem
Given experimental evidence at the LHC for physics beyond the standard model,
how can we determine the nature of the underlying theory? We initiate an
approach to studying the "inverse map" from the space of LHC signatures to the
parameter space of theoretical models within the context of low-energy
supersymmetry, using 1808 LHC observables including essentially all those
suggested in the literature and a 15 dimensional parametrization of the
supersymmetric standard model. We show that the inverse map of a point in
signature space consists of a number of isolated islands in parameter space,
indicating the existence of "degeneracies"--qualitatively different models with
the same LHC signatures. The degeneracies have simple physical
characterizations, largely reflecting discrete ambiguities in electroweak-ino
spectrum, accompanied by small adjustments for the remaining soft parameters.
The number of degeneracies falls in the range 1<d<100, depending on whether or
not sleptons are copiously produced in cascade decays. This number is large
enough to represent a clear challenge but small enough to encourage looking for
new observables that can further break the degeneracies and determine at the
LHC most of the SUSY physics we care about. Degeneracies occur because
signatures are not independent, and our approach allows testing of any new
signature for its independence. Our methods can also be applied to any other
theory of physics beyond the standard model, allowing one to study how model
footprints differ in signature space and to test ways of distinguishing
qualitatively different possibilities for new physics at the LHC.Comment: 55 pages, 30 figure
Search for single top quarks in the tau+jets channel using 4.8 fb of collision data
We present the first direct search for single top quark production using tau
leptons. The search is based on 4.8 fb of integrated luminosity
collected in collisions at =1.96 TeV with the D0 detector
at the Fermilab Tevatron Collider. We select events with a final state
including an isolated tau lepton, missing transverse energy, two or three jets,
one or two of them tagged. We use a multivariate technique to discriminate
signal from background. The number of events observed in data in this final
state is consistent with the signal plus background expectation. We set in the
tau+jets channel an upper limit on the single top quark cross section of
\TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected
sensitivity for the observation of single top production when combining it with
electron+jets and muon+jets channels already published by the D0 collaboration
with 2.3 fb of data. We measure a combined cross section of
\SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure
A Markov chain Monte Carlo analysis of the CMSSM
We perform a comprehensive exploration of the Constrained MSSM parameter space employing a Markov Chain Monte Carlo technique and a Bayesian analysis. We compute superpartner masses and other collider observables, as well as a cold dark matter abundance, and compare them with experimental data. We include uncertainties arising from theoretical approximations as well as from residual experimental errors of relevant Standard Model parameters. We delineate probability distributions of the CMSSM parameters, the collider and cosmological observables as well as a dark matter direct detection cross section. The 68% probability intervals of the CMSSM parameters are: 0.52 TeV < m1/2 < 1.26 TeV, m0 < 2.10 TeV, -0.34 TeV < A0 < 2.41 TeV and 38.5 < tan \u3b2 < 54.6. Generally, large fractions of high probability ranges of the superpartner masses will be probed at the LHC. For example, we find that the probability of mg < 2.7TeV is 78%, of mqR < 2.5TeV is 85% and of m\u3c7\ub11 < 0.8TeV is 65%. As regards the other observables, for example at 68% probability we find 3.5
710-9 < BR(Bs \u2192 \u3bc+\u3bc-) < 1.7
710-8, 1.9
710-10 < \u3b4a SUSY \u3bc < 9.9
710-10 and 1
7 10 -10 pb < \u3c3SIp < 1
7 10 -8 pb for direct WIMP detection. We highlight a complementarity between LHC and WIMP dark matter searches in exploring the CMSSM parameter space. We further expose a number of correlations among the observables, in particular between BR(Bs \u2192 \u3bc+\u3bc-) and BR(B \u2192 X s\u3b3) or \u3c3SIp. Once SUSY is discovered, this and other correlations may prove helpful in distinguishing the CMSSM from other supersymmetric models. We investigate the robustness of our results in terms of the assumed ranges of CMSSM parameters and the effect of the (g - 2)\u3bc anomaly which shows some tension with the other observables. We find that the results for m0, and the observables which strongly depend on it, are sensitive to our assumptions, while our conclusions for the other variables are robust
Search for pair production of the scalar top quark in the electron-muon final state
We report the result of a search for the pair production of the lightest
supersymmetric partner of the top quark () in
collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron
collider corresponding to an integrated luminosity of 5.4 fb. The scalar
top quarks are assumed to decay into a quark, a charged lepton, and a
scalar neutrino (), and the search is performed in the electron
plus muon final state. No significant excess of events above the standard model
prediction is detected, and improved exclusion limits at the 95% C.L. are set
in the the (,) mass plane
Past and present distribution, densities and movements of blue whales <i>Balaenoptera musculus</i> in the Southern Hemisphere and northern Indian Ocean
1Blue whale locations in the Southern Hemisphere and northern Indian Ocean were obtained from catches (303Â 239), sightings (4383 records of =8058 whales), strandings (103), Discovery marks (2191) and recoveries (95), and acoustic recordings.2Sighting surveys included 7Â 480Â 450Â km of effort plus 14Â 676Â days with unmeasured effort. Groups usually consisted of solitary whales (65.2%) or pairs (24.6%); larger feeding aggregations of unassociated individuals were only rarely observed. Sighting rates (groups per 1000Â km from many platform types) varied by four orders of magnitude and were lowest in the waters of Brazil, South Africa, the eastern tropical Pacific, Antarctica and South Georgia; higher in the Subantarctic and Peru; and highest around Indonesia, Sri Lanka, Chile, southern Australia and south of Madagascar.3Blue whales avoid the oligotrophic central gyres of the Indian, Pacific and Atlantic Oceans, but are more common where phytoplankton densities are high, and where there are dynamic oceanographic processes like upwelling and frontal meandering.4Compared with historical catches, the Antarctic (âtrueâ) subspecies is exceedingly rare and usually concentrated closer to the summer pack ice. In summer they are found throughout the Antarctic; in winter they migrate to southern Africa (although recent sightings there are rare) and to other northerly locations (based on acoustics), although some overwinter in the Antarctic.5Pygmy blue whales are found around the Indian Ocean and from southern Australia to New Zealand. At least four groupings are evident: northern Indian Ocean, from Madagascar to the Subantarctic, Indonesia to western and southern Australia, and from New Zealand northwards to the equator. Sighting rates are typically much higher than for Antarctic blue whales.6South-east Pacific blue whales have a discrete distribution and high sighting rates compared with the Antarctic. Further work is needed to clarify their subspecific status given their distinctive genetics, acoustics and length frequencies.7Antarctic blue whales numbered 1700 (95% Bayesian interval 860â2900) in 1996 (less than 1% of original levels), but are increasing at 7.3% per annum (95% Bayesian interval 1.4â11.6%). The status of other populations in the Southern Hemisphere and northern Indian Ocean is unknown because few abundance estimates are available, but higher recent sighting rates suggest that they are less depleted than Antarctic blue whales.</li
A systematic review of physical activity promotion strategies
This article was first published in:British Journal of Sports Medicine:1996:30:84-89We have reviewed randomised controlled trials of physical activity promotion to provide recent and reliable information on the effectiveness of physical activity promotion. Computerised databases and references of references were searched. Experts were contacted and asked for information about existing work. Studies assessed were randomised controlled trials of healthy, free living, adult subjects, where exercise behaviour was the dependent variable. Eleven trials were identified. No United Kingdom based studies were found. Interventions that encourage walking and do not require attendance at a facility are most likely to lead to sustainable increases in overall physical activity. Brisk walking has the greatest potential for increasing overall activity levels of a sedentary population and meeting current public health recommendations. The small number of trials limits the strength of any conclusions and highlights the need for more research
CONSORT Harms 2022 statement, explanation, and elaboration: updated guideline for the reporting of harms in randomised trials
Randomised controlled trials remain the reference standard for healthcare research on effects of interventions, and the need to report both benefits and harms is essential. The Consolidated Standards of Reporting Trials (the main CONSORT) statement includes one item on reporting harms (ie, all important harms or unintended effects in each group). In 2004, the CONSORT group developed the CONSORT Harms extension; however, it has not been consistently applied and needs to be updated. Here, we describe CONSORT Harms 2022, which replaces the CONSORT Harms 2004 checklist, and shows how CONSORT Harms 2022 items could be incorporated into the main CONSORT checklist. Thirteen items from the main CONSORT were modified to improve harms reporting. Three new items were added. In this article, we describe CONSORT Harms 2022 and how it was integrated into the main CONSORT checklist, and elaborate on each item relevant to complete reporting of harms in randomised controlled trials. Until future work from the CONSORT group produces an updated checklist, authors, journal reviewers, and editors of randomised controlled trials should use the integrated checklist presented in this paper
Conserved linkage of neurotrophin-3 and von Willebrand factor on mouse Chromosome 6
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47003/1/335_2004_Article_BF00357095.pd
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