1,991 research outputs found
Delineation of dominant and recessive forms of LZTR1-associated Noonan syndrome.
Noonan syndrome (NS) is characterised by distinctive facial features, heart defects, variable degrees of intellectual disability and other phenotypic manifestations. Although the mode of inheritance is typically dominant, recent studies indicate LZTR1 may be associated with both dominant and recessive forms. Seeking to describe the phenotypic characteristics of LZTR1-associated NS, we searched for likely pathogenic variants using two approaches. First, scrutiny of exomes from 9624 patients recruited by the Deciphering Developmental Disorders (DDDs) study uncovered six dominantly-acting mutations (p.R97L; p.Y136C; p.Y136H, p.N145I, p.S244C; p.G248R) of which five arose de novo, and three patients with compound-heterozygous variants (p.R210*/p.V579M; p.R210*/p.D531N; c.1149+1G>T/p.R688C). One patient also had biallelic loss-of-function mutations in NEB, consistent with a composite phenotype. After removing this complex case, analysis of human phenotype ontology terms indicated significant phenotypic similarities (P = 0.0005), supporting a causal role for LZTR1. Second, targeted sequencing of eight unsolved NS-like cases identified biallelic LZTR1 variants in three further subjects (p.W469*/p.Y749C, p.W437*/c.-38T>A and p.A461D/p.I462T). Our study strengthens the association of LZTR1 with NS, with de novo mutations clustering around the KT1-4 domains. Although LZTR1 variants explain ~0.1% of cases across the DDD cohort, the gene is a relatively common cause of unsolved NS cases where recessive inheritance is suspected
Diffractive Dijet Production at sqrt(s)=630 and 1800 GeV at the Fermilab Tevatron
We report a measurement of the diffractive structure function of
the antiproton obtained from a study of dijet events produced in association
with a leading antiproton in collisions at GeV at the
Fermilab Tevatron. The ratio of at GeV to
obtained from a similar measurement at GeV is compared with
expectations from QCD factorization and with theoretical predictions. We also
report a measurement of the (-Pomeron) and ( of parton in
Pomeron) dependence of at GeV. In the region
, GeV and , is
found to be of the form , which obeys
- factorization.Comment: LaTeX, 9 pages, Submitted to Phys. Rev. Letter
Measurement of the Helicity Fractions of W Bosons from Top Quark Decays Using Fully Reconstructed top-antitop Events with CDF II
We present a measurement of the fractions F_0 and F_+ of longitudinally
polarized and right-handed W bosons in top quark decays using data collected
with the CDF II detector. The data set used in the analysis corresponds to an
integrated luminosity of approximately 318 pb -1. We select ttbar candidate
events with one lepton, at least four jets, and missing transverse energy. Our
helicity measurement uses the decay angle theta*, which is defined as the angle
between the momentum of the charged lepton in the W boson rest frame and the W
momentum in the top quark rest frame. The cos(theta*) distribution in the data
is determined by full kinematic reconstruction of the ttbar candidates. We find
F_0 = 0.85 +0.15 -0.22 (stat) +- 0.06 (syst) and F_+ = 0.05 +0.11 -0.05 (stat)
+- 0.03 (syst), which is consistent with the standard model prediction. We set
an upper limit on the fraction of right-handed W bosons of F_+ < 0.26 at the
95% confidence level.Comment: 11 pages, 2 figures, submitted to Phys. Rev.
Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV
We search for the standard model Higgs boson produced in association with an
electroweak vector boson in events with no identified charged leptons, large
imbalance in transverse momentum, and two jets where at least one contains a
secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1
integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV
recorded by the CDF II experiment at the Tevatron. We find 268 (16) single
(double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are
expected from standard model background processes. We place 95% confidence
level upper limits on the Higgs boson production cross section for several
Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115
GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model
prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let
Forward-Backward Asymmetry in Top Quark Production in ppbar Collisions at sqrt{s}=1.96 TeV
Reconstructable final state kinematics and charge assignment in the reaction
ppbar->ttbar allows tests of discrete strong interaction symmetries at high
energy. We define frame dependent forward-backward asymmetries for the outgoing
top quark in both the ppbar and ttbar rest frames, correct for experimental
distortions, and derive values at the parton-level. Using 1.9/fb of ppbar
collisions at sqrt{s}=1.96 TeV recorded with the CDF II detector at the
Fermilab Tevatron, we measure forward-backward top quark production asymmetries
in the ppbar and ttbar rest frames of A_{FB,pp} = 0.17 +- 0.08 and A_{FB,tt} =
0.24 +- 0.14.Comment: 7 pages, 2 figures, submitted to Phys.Rev.Lett, corrected references
and change of tex
Search for a High-Mass Diphoton State and Limits on Randall-Sundrum Gravitons at CDF
We have performed a search for new particles which decay to two photons using
1.2/fb of integrated luminosity from p-pbar collisions at sqrt(s) = 1.96 TeV
collected using the CDF II Detector at the Fermilab Tevatron. We find the
diphoton mass spectrum to be in agreement with the standard model expectation,
and set limits on the cross section times branching ratio for the
Randall-Sundrum graviton, as a function of diphoton mass. We subsequently
derive lower limits for the graviton mass of 230 GeV/c2 and 850 GeV/c2, at the
95% confidence level, for coupling parameters (k/M_Pl) of 0.01 and 0.1
respectively.Comment: submitted to Phys. Rev. Let
First Measurement of the W Boson Mass in Run II of the Tevatron
We present a measurement of the W boson mass using 200/pb of data collected
in pbar p collisions at sqrt(s) = 1.96 TeV by the CDF II detector at Run II of
the Fermilab Tevatron. With a sample of 63964 W -> e nu candidates and 51128 W
-> mu nu candidates, we measure M_W = (80413 +- 34 (stat) +- 34 (syst) = 80413
+- 48) MeV/c^2. This is the most precise single measurement of the W boson mass
to date.Comment: published version in PR
Measurement of the Top-Quark Mass in All-Hadronic Decays in p pbar Collisions at CDF II
We present a measurement of the top-quark mass, , in the
all-hadronic decay channel . The analysis is performed using 310 pb of
=1.96 TeV collisions collected with the CDF II detector
using a multi-jet trigger. The mass measurement is based on an event-by-event
likelihood which depends on both the sample purity and the value of the
top-quark mass, using 90 possible jet-to-parton assignments in the six-jet
final state. The joint likelihood of 290 selected events yields a value of
=177.1 4.9 (stat.) 4.7 (syst.) GeV/.Comment: 7 pages, 2 figures and 1 table, Submitted to Phys. Rev. Let
A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab
We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the
creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c
s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at
sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron
collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi
K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) =
(1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from
psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)
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