Cine MRI Is Useful for the Diagnosis of Intradural Arachnoid Cyst with Spinal Arachnoid Web: A Case Report

CASE

A 28-year-old woman developed gait disturbance due to lower limb weakness 3 years before presentation. Conventional magnetic resonance imaging (MRI) findings were inconclusive; therefore, we performed cine MRI, which confirmed the presence of a pulsatile cyst on the posterior thoracic spinal cord. The cyst compressed the spinal cord, and its pulsations synchronized with the patient's heartbeats. We resected the intradural arachnoid cyst and thickened arachnoid membrane. The gait disturbance improved after surgery.

CONCLUSIONS

Cine MRI can be used to identify a pulsating arachnoid cyst that cannot be visualized with a conventional MRI. Cine MRI is useful in patients with unexplained spinal symptoms.

High-precision measurement of the W boson mass with the CDF II detector

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, M_W, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera-electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain [Formula: see text], the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega-electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

Association of Magnetic Resonance Imaging Features with Angioleiomyoma Histologic Subtype

BACKGROUND

Angioleiomyomas typically present as small, painful, soft-tissue tumors less than 2 cm in diameter. The features of angioleiomyomas on magnetic resonance (MR) imaging are not well understood, and the association of MR findings with histologic subtype is unclear. In the present study, the MR features of angioleiomyomas of average size were compared in relation to histologic subtype.

METHODS

This retrospective review of medical records analyzed MR imaging data and histologic specimens from 18 consecutive patients with angioleiomyomas that were resected at our hospital during the period from January 2006 through December 2013.

RESULTS

On T1-weighted images, lesions exhibited homogeneous areas that were isointense with skeletal muscle. However, T2-weighted images of solid and venous angioleiomyomas showed heterogeneous areas that were isointense or slightly hyperintense, while cavernous angioleiomyomas exhibited hyperintensity. Most lesions had a hypointense rim, and two thirds had adjacent vessels.

CONCLUSIONS

Our results suggest that MR findings for angioleiomyoma vary in relation to histologic subtype. T2-weighted images of solid and venous angioleiomyomas yielded specific MR findings that allowed for differentiation from other soft-tissue tumors, such as soft-tissue sarcomas. Most of these tumors exhibited isointense to slightly hyperintense regions, as compared with skeletal muscle, while findings for cavernous angioleiomyomas were nonspecific. Thus, clinical findings and MR imaging were almost sufficient for preoperative diagnosis of solid and venous angioleiomyomas.

Development and Verification of Educational Material for Plain Radiographic Diagnosis of Bone Metastasis: A Preliminary Report

Our previous studies showed that early diagnosis of painful bone metastasis is difficult and requires improvement in the diagnostic accuracy of plain radiography during an initial patient consultation. In this preliminary study, we evaluate the usefulness of educational material used to improve diagnosis of bone metastasis with plain radiography. This study included imaging data from 129 consecutive patients who visited our orthopedic clinic during the period January 2011 through December 2014. First, we prepared a test to measure the reading ability of orthopedic practitioners, after which the educational material was created. Then, the effectiveness of the educational material was verified by having orthopedic trainees take a pre-test and post-test. The test contained plain radiographic data from 12 patients with lesions and 6 without lesions. The educational material included plain radiographic data from 30 patients with typical findings of bone metastasis, as well as diagnostic magnetic resonance images or computed tomography scans, accompanied by a lecture. The accuracy and sensitivity of diagnosis significantly improved after the lecture; however, specificity decreased. Although the educational material was effective for improving the ability of orthopedic trainees to read plain radiographs of bone metastasis, some aspects of the program need to be improved and revised.

Effect of Orthopedics Promotional Activities on Multidisciplinary Management of Patients with Bone Metastases

BACKGROUND

The rapid aging of the Japanese population is leading to an increase in the number of patients with bone metastases. Since 2014, our orthopedics department has promoted multidisciplinary hospital activities, including offering lectures to hospital staff on multidisciplinary approaches for bone metastases and holding regular cancer board meetings on bone metastases. This study investigated whether these activities were effective in promoting multidisciplinary approaches and improving outcomes of patients with bone metastasis.

METHODS

To investigate the effects of changes in medical practice on patients with bone metastases, we compared patient clinical characteristics after (January 2014 through December 2017) and before the start of the activities (January 2011 through December 2013).

RESULTS

The semiannual numbers of first-visit, referral, and orthopedic surgical patients, the number of patients with slower growing primary cancers, and the number of patients with milder pain were significantly higher post-activity than pre-activity. The number of patients without paralysis was higher after the start of the activity than before the activity, but the difference was not significant. Survival after the first visit to the orthopedics department was significantly longer after the start of the activity than before the activity.

CONCLUSIONS

The potential demand for a multidisciplinary approach to bone metastases is high, and orthopedic specialists should actively participate in this approach.

Symptoms Related to Moderate Skeletal-Related Events as Clues for the Diagnosis of Bone Metastasis

BACKGROUND

Early diagnosis of bone metastasis is difficult. The aim of the present study was to determine whether symptoms related to skeletal-related events (SREs) can be used for the diagnosis of bone metastasis in the absence of screening tests.

METHODS

We reviewed 81 patients with bone metastasis to evaluate their SREs at diagnosis. SREs were arbitrarily classified as moderate or severe. Moderate SREs included radiation to the bone before pathological fracture or paralysis, bone surgery before pathological fracture or paralysis, and hypercalcemia without dialysis. Severe SREs included pathological fracture, spinal cord compression, and hypercalcemia necessitating dialysis.

RESULTS

The complication rates of SREs at the time the bone metastasis was diagnosed were 59.3% and 24.7% for severe and moderate SREs, respectively, and only 16.0% of cases were uncomplicated. The clinical factors that showed a significant relationship with the severity of SREs were age and history of malignancy. However, there was no significant relationship between the complication rate of total SREs and the presence or absence of a malignancy history (83.3% vs. 85.2%, respectively, p=0.83).

CONCLUSION

The results of the present study suggest that symptoms related to SREs can be used to diagnose bone metastasis in the absence of a screening test. Bone metastasis should be diagnosed as often as possible based on symptoms related to moderate SREs and should be treated as soon as possible before patients develop severe SREs.

Diagnosis of Bone Metastasis in Patients Without a History of Cancer

BACKGROUND

Diagnosing bone metastasis in patients without a history of cancer remains challenging. Diagnostic evaluation may be prolonged owing to difficulties in distinguishing between bone metastasis and common orthopedic diseases. We hypothesized that bone metastasis due to occult cancer would be more difficult to diagnose than bone metastasis in patients with a history of cancer. Few studies exist on the difficulty of diagnosing bone metastasis in patients without a history of cancer. Therefore, we reviewed the clinical course of patients with bone metastasis between January 2011 and December 2014.

METHODS

We reviewed patients with bone metastasis to determine the diagnostic rate at first visit, period from symptom-onset to first visit, period from first visit to diagnosis, and presence of severe skeletal-related events at diagnosis, and compared these between 27 patients without a history of cancer (Group A) and 54 patients with a history of cancer (Group B).

RESULTS

The diagnostic rate at first visit was significantly lower (11.5% vs. 52.4%, p=0.00069), the period from first visit to diagnosis was significantly longer (median, 7 weeks vs. 3 weeks, p=0.018), and the presence of severe skeletal-related events at diagnosis was significantly higher (81.4% vs. 50.0%, p=0.05) in patients without a history of cancer compared with those with a history of cancer.

CONCLUSIONS

The results of this study indicate that it is difficult to diagnose bone metastasis in patients without a history of cancer. This must be considered in the early diagnosis of bone metastasis to prevent severe skeletal-related events.

Challenges in the Diagnosis of bone Metastasis in Patients without a History of Malignancy at Their First Clinic Visit

BACKGROUND

Many patients with bone metastases whose diagnoses came only after they had suffered aggravated conditions are still frequently encountered. However, there have been few studies regarding the early diagnosis of such metastases. We retrospectively reviewed the clinical courses of cases we experienced between 2004 and 2014 to clarify the practical situation of diagnosis of such bone metastases.

METHODS

We undertook a retrospective review of 56 of our patients with bone metastasis who had no history of malignancy at their first visit, who visited our departments between 2004 and 2014. The initial diagnoses at the first visit to any clinic, the period from the first visit to any clinic to diagnosis of bone metastasis, the process to make the diagnosis, the frequency of severe skeletal-related events at diagnosis, and the examination serving as the basis for diagnosis were evaluated.

RESULTS

The diagnosis of bone metastasis was made at the first visit in only 6 of the 56 patients. Pathological fractures, paralysis and/or calcemia were seen in 62.5% of the patients at diagnosis of bone metastasis. The median period from the first visit to any clinic to diagnosis was 7.0 weeks. Typically, the diagnosis of bone metastasis was made only after aggravation. The most frequent examination to serve as the basis of diagnosis was magnetic resonance imaging.

CONCLUSIONS

Diagnosis of bone metastasis is challenging in patients without a history of malignancy at their first visit. For early diagnosis, it is important to recognize this challenge and to keep it in mind together with ongoing observation.

Diagnostic Value of Plain Radiography for Symptomatic Bone Metastasis at the First Visit

BACKGROUND

To prevent and minimize skeletal-related diseases, early diagnosis of bone metastases is important. However, previous reports have shown that plain radiography has low sensitivity and fails to screen multiple asymptomatic lesions. Limited investigations have been reported on the value of plain radiography in the diagnosis of symptomatic bone metastases. Therefore, this study aimed to investigate the diagnostic utility of plain radiography for symptomatic bone metastasis.

METHODS

Two experienced orthopedic surgeons retrospectively evaluated the plain radiographs of 39 patients with symptoms during their first visit between 2011 and 2014 for bone metastases. Another 2 experienced orthopedic surgeons then reviewed the data using 2 reference standards, the clinical results and the retrospectively evaluated results, in a blinded manner. The data were then reviewed by 2 certified orthopedic surgeons and 7 orthopedic surgeons in training with differing years of experience in a blinded manner.

RESULTS

The overall sensitivity of diagnosis of symptomatic bone metastasis using plain radiography at the clinic first visit was 71.4%. Upon blinded evaluation, the accuracy, sensitivity, and specificity were 55.8%, 54.3%, and 68.8% and 77.6%, 73.0%, and 85.7% for clinical results and results from 2 experienced orthopedic surgeons as a reference standard, retrospectively. There was a strong and significant correlation between the accuracy and observers' years of experience in orthopedic surgery among the orthopedic surgeons in training (R=0.942, p=0.0015).

CONCLUSIONS

Plain radiography around the time of the first visit has a definitive role in the early diagnosis of symptomatic bone metastasis.

Search for the Exotic Meson X(5568) with the Collider Detector at Fermilab

A search for the exotic meson X(5568) decaying into the B_{s}^{0}π^{±} final state is performed using data corresponding to 9.6  fb^{-1} from pp[over ¯] collisions at sqrt[s]=1960  GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7% at the 95% confidence level is set on the fraction of B_{s}^{0} produced through the X(5568)→B_{s}^{0}π^{±} process.

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is A_{FB}^{tt[over ¯]}=0.128±0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

Intercondylar fracture of the distal humerus in a 7-year-old child: A case report and a review of the literature

RATIONALE

Intercondylar fracture of the distal humerus is an extremely rare injury in children, especially in those under 8 years of age. To our best knowledge, there have been 55 reported cases of this fracture type in children in the English literature, 12 of which involved children under 8 years of age.

PATIENT CONCERNS

We report a case of intercondylar fracture of the distal humerus in a7-year-old boy fell in a gymnasium, injuring his left elbow.

INTERVENTIONS

Closed reduction was initially attempted under fluoroscopic guidance, but anatomic reduction could not be achieved because the fragments were extremely unstable and irreducible. Considering the displacement and the failure of closed reduction, ORIF through a posterior approach was performed. Open reduction and double cross-pinning across the medial and lateral condylar fragments were performed through a posterior approach.

DIAGNOSES

Plain radiographs showed a displaced intercondylar fracture of the distal humerus. Arthrography under general anesthesia showed a severely displaced intra-articular fracture, with rotational displacement of the lateral condyle.

OUTCOMES

Thirteen months after surgery, there was no functional disturbance or radiographic evidence of avascular necrosis or epiphyseal growth arrest.

LESSONS

Open reduction and double cross-pinning through a posterior approach can be a reliable procedure for intercondylar fracture of the distal humerus in children.

Increased ghrelin signaling prolongs survival in mouse models of human aging through activation of sirtuin1

Caloric restriction (CR) is known to retard aging and delay functional decline as well as the onset of diseases in most organisms. Ghrelin is secreted from the stomach in response to CR and regulates energy metabolism. We hypothesized that in CR ghrelin has a role in protecting aging-related diseases. We examined the physiological mechanisms underlying the ghrelin system during the aging process in three mouse strains with different genetic and biochemical backgrounds as animal models of accelerated or normal human aging. The elevated plasma ghrelin concentration was observed in both klotho-deficient and senescence-accelerated mouse prone/8 (SAMP8) mice. Ghrelin treatment failed to stimulate appetite and prolong survival in klotho-deficient mice, suggesting the existence of ghrelin resistance in the process of aging. However, ghrelin antagonist hastened death and ghrelin signaling potentiators rikkunshito and atractylodin ameliorated several age-related diseases with decreased microglial activation in the brain and prolonged survival in klotho-deficient, SAMP8 and aged ICR mice. In vitro experiments, the elevated sirtuin1 (SIRT1) activity and protein expression through the cAMP-CREB pathway was observed after ghrelin and ghrelin potentiator treatment in ghrelin receptor 1a-expressing cells and human umbilical vein endothelial cells. Furthermore, rikkunshito increased hypothalamic SIRT1 activity and SIRT1 protein expression of the heart in the all three mouse models of aging. Pericarditis, myocardial calcification and atrophy of myocardial and muscle fiber were improved by treatment with rikkunshito. Ghrelin signaling may represent one of the mechanisms activated by CR, and potentiating ghrelin signaling may be useful to extend health and lifespan.

Expression level of P2X7 receptor is a determinant of ATP-induced death of mouse cultured neurons

Activation of P2X7 receptor (P2X7R), a purinergic receptor, expressed by neurons is well-known to induce their death, but whether or not their sensitivity to ATP depends on its expression levels remains unclear. Here, we examined the effect of the expression level of P2X7Rs on cell viability using pure neuron cultures, co-cultures with astrocytes derived from SJL- and ddY-strain mice, and mouse P2X7R-expressing HEK293T cell systems. Treatment of pure neuron cultures with 5mM ATP for 2h, followed by 3-h incubation in fresh medium, resulted in death of both types of neurons, and their death was prevented by administration of P2X7R-specific antagonists. In both SJL- and ddY-neurons, ATP-induced neuronal death was inhibited by a mitochondrial permeability transition pore inhibitor cyclosporine A, mitochondrial dysfunction being involved in their death. The ATP-induced neuronal death was greater for SJL-neurons than for ddY-ones, this being correlated with the expression level of P2X7R in them, and the same results were obtained for the HEK293T cell systems. Co-culture of neurons with astrocytes increased the ATP-induced neuronal death compared to the case of pure neuron cultures. Overall, we reveal that neuronal vulnerability to ATP depends on the expression level of P2X7R, and co-existence of astrocytes exacerbates ATP-induced neuronal death.

On-tip photodetection: a simple and universal platform for optoelectronic screening

A novel platform for transient photodetector component screening has been developed whereby an optical fiber tip serves as the counter electrode when placed in a variety of dielectric media, connected to a photoresponsive working electrode. The soft processing conditions allow for ubiquitous photodetection for organic and biological systems.

Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V_{tb}

We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^{-1} per experiment. The t-channel cross section is measured to be σ_{t}=2.25_{-0.31}^{+0.29} pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_{s+t}=3.30_{-0.40}^{+0.52} pb, without assuming the standard model value for the ratio σ_{s}/σ_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L.

Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment

We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √[s]=1.96  TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5  fb(-1). No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W'→tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900  GeV/c(2) range. The limits presented here are the most stringent for a charged resonance with mass in the range 300-600  GeV/c(2) decaying to top and bottom quarks.

Tevatron constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quark pairs

Combined constraints from the CDF and D0 Collaborations on models of the Higgs boson with exotic spin J and parity P are presented and compared with results obtained assuming the standard model value JP=0+. Both collaborations analyzed approximately 10  fb(-) of proton-antiproton collisions with a center-of-mass energy of 1.96 TeV collected at the Fermilab Tevatron. Two models predicting exotic Higgs bosons with JP=0- and JP=2+ are tested. The kinematic properties of exotic Higgs boson production in association with a vector boson differ from those predicted for the standard model Higgs boson. Upper limits at the 95% credibility level on the production rates of the exotic Higgs bosons, expressed as fractions of the standard model Higgs boson production rate, are set at 0.36 for both the JP=0- hypothesis and the JP=2+ hypothesis. If the production rate times the branching ratio to a bottom-antibottom pair is the same as that predicted for the standard model Higgs boson, then the exotic bosons are excluded with significances of 5.0 standard deviations and 4.9 standard deviations for the JP=0- and JP=2+ hypotheses, respectively.

Constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quarks in the full CDF data set

A search for particles with the same mass and couplings as those of the standard model Higgs boson but different spin and parity quantum numbers is presented. We test two specific alternative Higgs boson hypotheses: a pseudoscalar Higgs boson with spin-parity J^{P}=0^{-} and a gravitonlike Higgs boson with J^{P}=2^{+}, assuming for both a mass of 125  GeV/c^{2}. We search for these exotic states produced in association with a vector boson and decaying into a bottom-antibottom quark pair. The vector boson is reconstructed through its decay into an electron or muon pair, or an electron or muon and a neutrino, or it is inferred from an imbalance in total transverse momentum. We use expected kinematic differences between events containing exotic Higgs bosons and those containing standard model Higgs bosons. The data were collected by the CDF experiment at the Tevatron proton-antiproton collider, operating at a center-of-mass energy of sqrt[s]=1.96  TeV, and correspond to an integrated luminosity of 9.45  fb^{-1}. We exclude deviations from the predictions of the standard model with a Higgs boson of mass 125  GeV/c^{2} at the level of 5 standard deviations, assuming signal strengths for exotic boson production equal to the prediction for the standard model Higgs boson, and set upper limits of approximately 30% relative to the standard model rate on the possible rate of production of each exotic state.

Measurement of the single top quark production cross section and |Vtb| in events with one charged lepton, large missing transverse energy, and jets at CDF

We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV using a data set corresponding to 7.5  fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process t→Wb→ℓνb by requiring the presence of an electron or muon, a large imbalance of transverse momentum indicating the presence of a neutrino, and two or three jets including at least one originating from a bottom quark. An artificial neural network is used to discriminate the signal from backgrounds. We measure a single top quark production cross section of 3.04(-0.53)(+0.57)  pb and set a lower limit on the magnitude of the coupling between the top quark and bottom quark |Vtb|>0.78 at the 95% credibility level.

Measurements of direct CP-violating asymmetries in charmless decays of bottom baryons

We report final measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete √s=1.96  TeV proton-antiproton collisions data set, corresponding to 9.3  fb⁻¹ of integrated luminosity, we measure A(Λ(b)⁰→pπ⁻)=+0.06±0.07(stat)±0.03(syst) and A(Λ(b)⁰→pK⁻)=-0.10±0.08(stat)±0.04(syst), compatible with no asymmetry. In addition we measure the CP-violating asymmetries in B(s)⁰→K⁻π⁺ and B⁰→K⁺π⁻ decays to be A(B(s)⁰→K⁻π⁺)=+0.22±0.07(stat)±0.02(syst) and A(B⁰→K⁺π⁻)=-0.083±0.013(stat)±0.004(syst), respectively, which are significantly different from zero and consistent with current world averages.

Measurement of the inclusive leptonic asymmetry in top-quark pairs that decay to two charged leptons at CDF

We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions and decaying to final states that contain two charged leptons (electrons or muons). The data are collected with the Collider Detector at Fermilab and correspond to an integrated luminosity of 9.1 fb(-1). We measure the leptonic forward-backward asymmetry, A(FB)(ℓ), to be 0.072 ± 0.060 and the leptonic pair forward-backward asymmetry, A(FB)(ℓℓ), to be 0.076 ± 0.082. The measured values can be compared with the standard model predictions of A(FB)(ℓ) = 0.038 ± 0.003 and A(FB)(ℓℓ) = 0.048 ± 0.004, respectively. Additionally, we combine the A(FB)(ℓ) result with a previous determination from a final state with a single lepton and hadronic jets and obtain A(FB)(ℓ) = 0.090(-0.026)(+0.028).

Evidence for s-channel single-top-quark production in events with one charged lepton and two jets at CDF

We report evidence for s-channel single-top-quark production in proton-antiproton collisions at center-of-mass energy sqrt[s] = 1.96 TeV using a data set that corresponds to an integrated luminosity of 9.4 fb(-1) collected by the Collider Detector at Fermilab. We select events consistent with the s-channel process including two jets and one leptonically decaying W boson. The observed significance is 3.8 standard deviations with respect to the background-only prediction. Assuming a top-quark mass of 172.5 GeV/c(2), we measure the s-channel cross section to be 1.41(-0.42)(+0.44) pb.

Search for s-channel single-top-quark production in events with missing energy plus jets in pp collisions at sqrt[s] = 1.96 TeV

The first search for single-top-quark production from the exchange of an s-channel virtual W boson using events with an imbalance in the total transverse energy, b-tagged jets, and no identified leptons is presented. Assuming the electroweak production of top quarks of mass 172.5 GeV/c(2) in the s channel, a cross section of 1.12(-0.57)(+0.61) (stat+syst) pb with a significance of 1.9 standard deviations is measured. This measurement is combined with the result obtained from events with an imbalance in total transverse momentum, b-tagged jets, and exactly one identified lepton, yielding a cross section of 1.36(-0.32)(+0.37) (stat+syst) pb, with a significance of 4.2 standard deviations.

Observation of s-channel production of single top quarks at the Tevatron

We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb(-1) per experiment. The measured cross section is σ(s) = 1.29(-0.24)(+0.26) pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is 1.8 × 10(-10), corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks.

Measurement of B(t→Wb)/B(t→Wq) in top-quark-pair decays using dilepton events and the full CDF Run II data set

We present a measurement of the ratio of the top-quark branching fractions R=B(t→Wb)/B(t→Wq), where q represents any quark flavor, in events with two charged leptons, imbalance in total transverse energy, and at least two jets. The measurement uses proton-antiproton collision data at center-of-mass energy 1.96 TeV, corresponding to an integrated luminosity of 8.7  fb^{-1} collected with the Collider Detector at Fermilab during Run II of the Tevatron. We measure R to be 0.87±0.07, and extract the magnitude of the top-bottom quark coupling to be |V_{tb}|=0.93±0.04, assuming three generations of quarks. Under these assumptions, a lower limit of |V_{tb}|>0.85(0.87) at 95% (90%) credibility level is set.

First search for exotic Z Boson decays into photons and neutral pions in hadron collisions

A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb(-1) of integrated luminosity from proton-antiproton collisions at √s = 1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01 × 10(-5) for Z → π(0)γ, 1.46 × 10(-5) for Z → γγ, and 1.52 × 10(-5) for Z → π(0)π(0). The Z → π(0)γ and Z → γγ limits improve the most stringent results from other experiments by factors of 2.6 and 3.6, respectively. The Z → π(0)π(0) branching ratio limit is the first experimental result on this decay.

Observation of D⁰-D¯⁰ mixing using the CDF II detector

We measure the time dependence of the ratio of decay rates for D0→K(+)π(-) to the Cabibbo-favored decay D(0)→K(-)π(+). The charge conjugate decays are included. A signal of 3.3×10(4) D(*+)→π(+)D(0), D(0)→K(+)π(-) decays is obtained with D0 proper decay times between 0.75 and 10 mean D0 lifetimes. The data were recorded with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of 9.6  fb(-1) for pp¯ collisions at √s=1.96  TeV. Assuming CP conservation, we search for D0-D¯0 mixing and measure the mixing parameters to be R(D)=(3.51±0.35)×10(-3), y'=(4.3±4.3)×10(-3), and x'2=(0.08±0.18)×10(-3). We report Bayesian probability intervals in the x'2-y' plane and find that the significance of excluding the no-mixing hypothesis is equivalent to 6.1 Gaussian standard deviations, providing the second observation of D0-D¯0 mixing from a single experiment.

Direct measurement of the total decay width of the top quark

We present a measurement of the total decay width of the top quark using events with top-antitop quark pair candidates reconstructed in the final state with one charged lepton and four or more hadronic jets. We use the full Tevatron run II data set of sqrt[s]=1.96  TeV proton-antiproton collisions recorded by the CDF II detector. The top quark mass and the mass of the hadronically decaying W boson are reconstructed for each event and compared with distributions derived from simulated signal and background samples to extract the top quark width (Γtop) and the energy scale of the calorimeter jets with in situ calibration. For a top quark mass Mtop=172.5  GeV/c2, we find 1.10<Γtop<4.05  GeV at 68% confidence level, which is in agreement with the standard model expectation of 1.3 GeV and is the most precise direct measurement of the top quark width to date.

Measurement of the differential cross section dσ/d(cosθ(t)) for Top-Quark Pair Production in pp Collisions at sqrt[s] = 1.96 TeV

We report a measurement of the differential cross section dσ/d(cosθ(t)) for top-quark pair production as a function of the top-quark production angle in proton-antiproton collisions at sqrt[s] = 1.96 TeV. This measurement is performed using data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.4 fb(-1). We employ the Legendre polynomials to characterize the shape of the differential cross section at the parton level. The observed Legendre coefficients are in good agreement with the prediction of the next-to-leading-order standard-model calculation, with the exception of an excess linear-term coefficient a(1) = 0.40 ± 0.12, compared to the standard-model prediction of a(1)=0.15(-0.03)(+0.07).

Measurement of the cross section for direct-photon production in association with a heavy quark in pp[over ¯] collisions at sqrt[s]=1.96 TeV

We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of sqrt[s]=1.96  TeV proton-antiproton collisions corresponding to 9.1  fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|<1.0, a heavy-quark-jet transverse momentum pTjet>20  GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions.