Measurement of Exclusive B Decays to Final States Containing a Charmed Baryon

Using data collected by the CLEO detector in the Upsilon(4S) region, we report new measurements of the exclusive decays of B mesons into final states of the type Lambda_c^+ p-bar n(pi), where n=0,1,2,3. We find signals in modes with one, two and three pions and an upper limit for the two body decay Lambda_c^+ pbar. We also make the first measurements of exclusive decays of B mesons to Sigma_c p-bar n(pi), where n=0,1,2. We find signals in modes with one and two pions and an upper limit for the two body decay Sigma_c p-bar. Measurements of these modes shed light on the mechanisms involved in B decays to baryons.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

Measurement of the Masses and Widths of the Sigma_c^++ and Sigma_c^0 Charmed Baryons

Using data recorded by the CLEO II and CLEO II.V detector configurations at CESR, we report new measurements of the masses of the Sigma_c^{++} and Sigma_c^0 charmed baryons, and the first measurements of their intrinsic widths. We find M(Sigma_c^{++}) - M(Lambda_c^+) = 167.4 +- 0.1 +- 0.2 MeV, Gamma(Sigma_c^{++}) = 2.3 +- 0.2 +- 0.3 MeV, and M(Sigma_c^0) - M(Lambda_c^+) = 167.2 +- 0.1 +- 0.2 MeV, Gamma(Sigma_c^0) = 2.5 +- 0.2 +- 0.3 MeV, where the uncertainties are statistical and systematic, respectively.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PRD, Rapid Communications. Reference [13] correcte

Arachnoid cysts do not contain cerebrospinal fluid: A comparative chemical analysis of arachnoid cyst fluid and cerebrospinal fluid in adults

<p>Abstract</p> <p>Background</p> <p>Arachnoid cyst (AC) fluid has not previously been compared with cerebrospinal fluid (CSF) from the same patient. ACs are commonly referred to as containing "CSF-like fluid". The objective of this study was to characterize AC fluid by clinical chemistry and to compare AC fluid to CSF drawn from the same patient. Such comparative analysis can shed further light on the mechanisms for filling and sustaining of ACs.</p> <p>Methods</p> <p>Cyst fluid from 15 adult patients with unilateral temporal AC (9 female, 6 male, age 22-77y) was compared with CSF from the same patients by clinical chemical analysis.</p> <p>Results</p> <p>AC fluid and CSF had the same osmolarity. There were no significant differences in the concentrations of sodium, potassium, chloride, calcium, magnesium or glucose. We found significant elevated concentration of phosphate in AC fluid (0.39 versus 0.35 mmol/L in CSF; <it>p </it>= 0.02), and significantly reduced concentrations of total protein (0.30 versus 0.41 g/L; <it>p </it>= 0.004), of ferritin (7.8 versus 25.5 ug/L; <it>p </it>= 0.001) and of lactate dehydrogenase (17.9 versus 35.6 U/L; <it>p </it>= 0.002) in AC fluid relative to CSF.</p> <p>Conclusions</p> <p>AC fluid is not identical to CSF. The differential composition of AC fluid relative to CSF supports secretion or active transport as the mechanism underlying cyst filling. Oncotic pressure gradients or slit-valves as mechanisms for generating fluid in temporal ACs are not supported by these results.</p

Using PIV to measure granular temperature in saturated unsteady polydisperse granular flows

The motion of debris flows, gravity-driven fast moving mixtures of rock, soil and water can be interpreted using the theories developed to describe the shearing motion of highly concentrated granular fluid flows. Frictional, collisional and viscous stress transfer between particles and fluid characterizes the mechanics of debris flows. To quantify the influence of collisional stress transfer, kinetic models have been proposed. Collisions among particles result in random fluctuations in their velocity that can be represented by their granular temperature, T. In this paper particle image velocimetry, PIV, is used to measure the instantaneous velocity field found internally to a physical model of an unsteady debris flow created by using “transparent soil”—i.e. a mixture of graded glass particles and a refractively matched fluid. The ensemble possesses bulk properties similar to that of real soil-pore fluid mixtures, but has the advantage of giving optical access to the interior of the flow by use of plane laser induced fluorescence, PLIF. The relationship between PIV patch size and particle size distribution for the front and tail of the flows is examined in order to assess their influences on the measured granular temperature of the system. We find that while PIV can be used to ascertain values of granular temperature in dense granular flows, due to increasing spatial correlation with widening gradation, a technique proposed to infer the true granular temperature may be limited to flows of relatively uniform particle size or large bulk

Evidence for the Decay D0→K+π−π+π−D^0\to K^+ \pi^-\pi^+\pi^-

We present a search for the ``wrong-sign'' decay D0 -> K+ pi- pi+ pi- using 9 fb-1 of e+e- collisions on and just below the Upsilon(4S) resonance. This decay can occur either through a doubly Cabibbo-suppressed process or through mixing to a D0bar followed by a Cabibbo-favored process. Our result for the time-integrated wrong-sign rate relative to the decay D0 -> K- pi+ pi- pi+ is (0.0041 +0.0012-0.0011(stat.) +-0.0004(syst.))x(1.07 +-0.10)(phase space), which has a statistical significance of 3.9 standard deviations.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

Whole brain radiotherapy after local treatment of brain metastases in melanoma patients - a randomised phase III trial

<p>Abstract</p> <p>Background</p> <p>Cerebral metastases are a common cause of death in patients with melanoma. Systemic drug treatment of these metastases is rarely effective, and where possible surgical resection and/or stereotactic radiosurgery (SRS) are the preferred treatment options. Treatment with adjuvant whole brain radiotherapy (WBRT) following neurosurgery and/or SRS is controversial. Proponents of WBRT report prolongation of intracranial control with reduced neurological events and better palliation. Opponents state melanoma is radioresistant; that WBRT yields no survival benefit and may impair neurocognitive function. These opinions are based largely on studies in other tumour types in which assessment of neurocognitive function has been incomplete.</p> <p>Methods/Design</p> <p>This trial is an international, prospective multi-centre, open-label, phase III randomised controlled trial comparing WBRT to observation following local treatment of intracranial melanoma metastases with surgery and/or SRS. Patients aged 18 years or older with 1-3 brain metastases excised and/or stereotactically irradiated and an ECOG status of 0-2 are eligible. Patients with leptomeningeal disease, or who have had previous WBRT or localised treatment for brain metastases are ineligible. WBRT prescription is at least 30 Gy in 10 fractions commenced within 8 weeks of surgery and/or SRS. Randomisation is stratified by the number of cerebral metastases, presence or absence of extracranial disease, treatment centre, sex, radiotherapy dose and patient age. The primary endpoint is the proportion of patients with distant intracranial failure as determined by MRI assessment at 12 months. Secondary end points include: survival, quality of life, performance status and neurocognitive function.</p> <p>Discussion</p> <p>Accrual to previous trials for patients with brain metastases has been difficult, mainly due to referral bias for or against WBRT. This trial should provide the evidence that is currently lacking in treatment decision-making for patients with melanoma brain metastases. The trial is conducted by the Australia and New Zealand Melanoma Trials Group (ANZMTG-study 01-07), and the Trans Tasman Radiation Oncology Group (TROG) but international participation is encouraged. Twelve sites are open to date with 43 patients randomised as of the 31st March 2011. The target accrual is 200 patients.</p> <p>Trial registration</p> <p>Australia and New Zealand Clinical Trials Register (ANZCTR): <a href="http://www.anzctr.org.au/ACTRN12607000512426.aspx">ACTRN12607000512426</a></p

Hadronic Mass Moments in Inclusive Semileptonic B Meson Decays

We have measured the first and second moments of the hadronic mass-squared distribution in B -> X_c l nu, for P(lepton) > 1.5 GeV/c. We find <M_X^2 - M_D[Bar]^2> = 0.251 +- 0.066 GeV^2, )^2 > = 0.576 +- 0.170 GeV^4, where M_D[Bar] is the spin-averaged D meson mass. From that first moment and the first moment of the photon energy spectrum in b -> s gamma, we find the HQET parameter lambda_1 (MS[Bar], to order 1/M^3 and beta_0 alpha_s^2) to be -0.24 +- 0.11 GeV^2. Using these first moments and the B semileptonic width, and assuming parton-hadron duality, we obtain |V_cb| = 0.0404 +- 0.0013.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

Observation of Exclusive barB --> D(*) K*- Decays

We report the first observation of the exclusive decays \bar B\to D^{(*)}K^{*-}, using 9.66 x 10^{6} B\bar{B} pairs collected at the \Upsilon(4S) with the CLEO detector. We measure the following branching fractions: {\cal B}(B^- -> D^0 K^{*-})=(6.1 +- 1.6 +-1.7)x10^{-4}, {\cal B}(\bar{B^0} -> D^+K^{*-})=(3.7 +- 1.5 +- 1.0) x 10^{-4}, {\cal B}(\bar{B^0} -> D^{*+}K^{*-})=(3.8 +- 1.3 +- 0.8) x 10^{-4} and {\cal B}(B^- --> D^{*0} K^{*-})=(7.7 +- 2.2 +- 2.6) x 10^{-4}. The \bar B ->D^*K^{*-} branching ratios are the averages of those corresponding to the 00 and 11 helicity states. The errors shown are statistical and systematic, respectively.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, Published in Phys.Rev.Lett.88:101803,200

Observation of the Ωc0\Omega_{c}^{0} Charmed Baryon at CLEO

The CLEO experiment at the CESR collider has used 13.7 fb$^{-1}$ of data to search for the production of the $\Omega_c^0$ (css-ground state) in $e^{+}e^{-}$ collisions at $\sqrt{s} \simeq 10.6$ {\rm GeV}. The modes used to study the $\Omega_c^0$ are $\Omega^- \pi^+$, $\Omega^- \pi^+ \pi^0$, $\Xi^- K^- pi^+ \pi^+$, $\Xi^0 K^- pi^+$, and $\Omega^- \pi^+ \pi^- \pi^+$. We observe a signal of 40.4$\pm$9.0(stat) events at a mass of 2694.6$\pm$2.6(stat)$\pm$1.9(syst) {\rm MeV/$c^2$}, for all modes combined.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Observation of B→ϕKB\to \phi K and B→ϕK∗B\to \phi K^{*}

We have studied two-body charmless hadronic decays of $B$ mesons into the final states phi K and phi K^*. Using 9.7 million $B\bar{B}$ pairs collected with the CLEO II detector, we observe the decays B- -> phi K- and B0 -> phi K*0 with the following branching fractions: BR(B- -> phi K-)=(5.5 +2.1-1.8 +- 0.6) x 10^{-6} and BR(B0 -> phi K*0)=(11.5 +4.5-3.7 +1.8-1.7) x 10^{-6}. We also see evidence for the decays B0 -> phi K0 and B- -> phi K*-. However, since the statistical significance is not overwhelming for these modes we determine upper limits of <12.3 x 10^{-6} and <22.5 x 10^{-6} (90% C.L.) respectively.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN