844 research outputs found
Search for New Physics in e mu X Data at D0 Using Sleuth: A Quasi-Model-Independent Search Strategy for New Physics
We present a quasi-model-independent search for the physics responsible for
electroweak symmetry breaking. We define final states to be studied, and
construct a rule that identifies a set of relevant variables for any particular
final state. A new algorithm ("Sleuth") searches for regions of excess in those
variables and quantifies the significance of any detected excess. After
demonstrating the sensitivity of the method, we apply it to the semi-inclusive
channel e mu X collected in 108 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV
at the D0 experiment during 1992-1996 at the Fermilab Tevatron. We find no
evidence of new high p_T physics in this sample.Comment: 23 pages, 12 figures. Submitted to Physical Review
Search For Heavy Pointlike Dirac Monopoles
We have searched for central production of a pair of photons with high
transverse energies in collisions at TeV using of data collected with the D\O detector at the Fermilab Tevatron in
1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could
rescatter pairs of nearly real photons into this final state via a box diagram.
We observe no excess of events above background, and set lower 95% C.L. limits
of on the mass of a spin 0, 1/2, or 1 Dirac
monopole.Comment: 12 pages, 4 figure
The Dijet Mass Spectrum and a Search for Quark Compositeness in bar{p}p Collisions at sqrt{s} = 1.8 TeV
Using the DZero detector at the 1.8 TeV pbarp Fermilab Tevatron collider, we
have measured the inclusive dijet mass spectrum in the central pseudorapidity
region |eta_jet| < 1.0 for dijet masses greater than 200 Gev/c^2. We have also
measured the ratio of spectra sigma(|eta_jet| < 0.5)/sigma(0.5 < |eta_jet| <
1.0). The order alpha_s^3 QCD predictions are in good agreement with the data
and we rule out models of quark compositeness with a contact interaction scale
< 2.4 TeV at the 95% confidence level.Comment: 11 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
Search for High Mass Photon Pairs in p-pbar --> gamma-gamma-jet-jet Events at sqrt(s)=1.8 TeV
A search has been carried out for events in the channel p-barp --> gamma
gamma jet jet. Such a signature can characterize the production of a
non-standard Higgs boson together with a W or Z boson. We refer to this
non-standard Higgs, having standard model couplings to vector bosons but no
coupling to fermions, as a "bosonic Higgs." With the requirement of two high
transverse energy photons and two jets, the diphoton mass (m(gamma gamma))
distribution is consistent with expected background. A 90(95)% C.L. upper limit
on the cross section as a function of mass is calculated, ranging from
0.60(0.80) pb for m(gamma gamma) = 65 GeV/c^2 to 0.26(0.34) pb for m(gamma
gamma) = 150 GeV/c^2, corresponding to a 95% C.L. lower limit on the mass of a
bosonic Higgs of 78.5 GeV/c^2.Comment: 9 pages, 3 figures. Replacement has new H->gamma gamma branching
ratios and corresponding new mass limit
Zgamma Production in pbarp Collisions at sqrt(s)=1.8 TeV and Limits on Anomalous ZZgamma and Zgammagamma Couplings
We present a study of Z +gamma + X production in p-bar p collisions at
sqrt{S}=1.8 TeV from 97 (87) pb^{-1} of data collected in the eegamma
(mumugamma) decay channel with the D0 detector at Fermilab. The event yield and
kinematic characteristics are consistent with the Standard Model predictions.
We obtain limits on anomalous ZZgamma and Zgammagamma couplings for form factor
scales Lambda = 500 GeV and Lambda = 750 GeV. Combining this analysis with our
previous results yields 95% CL limits |h{Z}_{30}| < 0.36, |h{Z}_{40}| < 0.05,
|h{gamma}_{30}| < 0.37, and |h{gamma}_{40}| < 0.05 for a form factor scale
Lambda=750 GeV.Comment: 17 Pages including 2 Figures. Submitted to PR
Probing Hard Color-Singlet Exchange in ppbar Collisions at root-s=630 GeV and 1800 GeV
We present results on dijet production via hard color-singlet exchange in
proton-antiproton collisions at root-s = 630 GeV and 1800 GeV using the DZero
detector. The fraction of dijet events produced via color-singlet exchange is
measured as a function of jet transverse energy, separation in pseudorapidity
between the two highest transverse energy jets, and proton-antiproton
center-of-mass energy. The results are consistent with a color-singlet fraction
that increases with an increasing fraction of quark-initiated processes and
inconsistent with two-gluon models for the hard color-singlet.Comment: 16 pages, 6 figure
A Measurement of the W Boson Mass
We report a measurement of the W boson mass based on an integrated luminosity
of 82 pb from \ppbar collisions at TeV recorded in
1994--1995 by the \Dzero detector at the Fermilab Tevatron. We identify W
bosons by their decays to and extract the mass by fitting the transverse
mass spectrum from 28,323 W boson candidates. A sample of 3,563 dielectron
events, mostly due to Z to ee decays, constrains models of W boson production
and the detector. We measure \mw=80.44\pm0.10(stat)\pm0.07(syst)~GeV. By
combining this measurement with our result from the 1992--1993 data set, we
obtain \mw=80.43\pm0.11 GeV.Comment: 11 pages, 5 figure
SPIRE - combining SGI-110 with cisplatin and gemcitabine chemotherapy for solid malignancies including bladder cancer: study protocol for a phase Ib/randomised IIa open label clinical trial
Background
Urothelial bladder cancer (UBC) accounts for 10,000 new diagnoses and 5000 deaths annually in the UK (Cancer Research UK, http://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/bladder-cancer, Cancer Research UK, Accessed 26 Mar 2018). Cisplatin-based chemotherapy is standard of care therapy for UBC for both palliative first-line treatment of advanced/metastatic disease and radical neoadjuvant treatment of localised muscle invasive bladder cancer. However, cisplatin resistance remains a critical cause of treatment failure and a barrier to therapeutic advance in UBC. Based on supportive pre-clinical data, we hypothesised that DNA methyltransferase inhibition would circumvent cisplatin resistance in UBC and potentially other cancers.
Methods
The addition of SGI-110 (guadecitabine, a DNA methyltransferase inhibitor) to conventional doublet therapy of gemcitabine and cisplatin (GC) is being tested within the phase Ib/IIa SPIRE clinical trial. SPIRE incorporates an initial, modified rolling six-dose escalation phase Ib design of up to 36 patients with advanced solid tumours followed by a 20-patient open-label randomised controlled dose expansion phase IIa component as neoadjuvant treatment for UBC. Patients are being recruited from UK secondary care sites. The dose escalation phase will determine a recommended phase II dose (RP2D, primary endpoint) of SGI-110, by subcutaneous injection, on days 1–5 for combination with GC at conventional doses (cisplatin 70 mg/m2, IV infusion, day 8; gemcitabine 1000 mg/m2, IV infusion, days 8 and 15) in every 21-day cycle. In the dose expansion phase, patients will be randomised 1:1 to GC with or without SGI-110 at the proposed RP2D. Secondary endpoints will include toxicity profiles, SGI-110 pharmacokinetics and pharmacodynamic biomarkers, and pathological complete response rates in the dose expansion phase. Analyses will not be powered for formal statistical comparisons and descriptive statistics will be used to describe rates of toxicity, efficacy and translational endpoints by treatment arm.
Discussion
SPIRE will provide evidence for whether SGI-110 in combination with GC chemotherapy is safe and biologically effective prior to future phase II/III trials as a neoadjuvant therapy for UBC and potentially in other cancers treated with GC
Dutch women with a low birth weight have an increased risk of myocardial infarction later in life: a case control study
BACKGROUND: To investigate whether low birth weight increases the risk of myocardial infarction later in life in women. METHODS: Nationwide population-based case-control study. Patients and controls: 152 patients with a first myocardial infarction before the age of 50 years in the Netherlands. 568 control women who had not had a myocardial infarction stratified for age, calendar year of the index event, and area of residence. RESULTS: Birth weight in the patient group was significantly lower than in control women (3214 vs. 3370 gram, mean difference -156.3 gram (95%CI -9.5 to -303.1). The odds ratio for myocardial infarction, associated with a birth weight lower than 3000 gram (20(th )percentile in controls) compared to higher than 3000 gram was 1.7 (95%CI 1.1–2.7), while the odds ratio for myocardial infarction for children with a low birth weight (< 2000 g) compared to a birth weight ≥ 2000 g was 2.4 (95%CI 1.0 – 5.8). Both figures did not change after adjustment for putative confounders (age, education level, body mass index, waist-hip ratio, hypertension, diabetes, hypercholesterolemia, smoking, and family history of cardiovascular disease). CONCLUSIONS: Low birth weight is associated with an increased risk of myocardial infarction before age of 50 in Dutch women
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