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T. E. Coan

Publications and source records attributed to T. E. Coan.

53 records · Page 3Linked to original sources
arXiv2016

First measurement of electron neutrino appearance in NOvA

We report results from the first search for $ν_μ\toν_e$ transitions by the NOvA experiment. In an exposure equivalent to $2.74\times10^{20}$ protons-on-target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared to a background expectation of $0.99\pm0.11$ (syst.) events based on the Near Detector measurement. A secondary analysis observes 11 events with a background of $1.07\pm0.14$ (syst.). The $3.3σ$ excess of events observed in the primary analysis disfavors $0.1π< δ_{CP} < 0.5π$ in the inverted mass hierarchy at the 90% C.L.

hep-ex↗
arXiv2016

First measurement of muon-neutrino disappearance in NOvA

This paper reports the first measurement using the NOvA detectors of $ν_μ$ disappearance in a $ν_μ$ beam. The analysis uses a 14 kton-equivalent exposure of $2.74 \times 10^{20}$ protons-on-target from the Fermilab NuMI beam. Assuming the normal neutrino mass hierarchy, we measure $Δm^{2}_{32}=(2.52^{+0.20}_{-0.18})\times 10^{-3}$ eV$^{2}$ and $\sin^2θ_{23}$ in the range 0.38-0.65, both at the 68% confidence level, with two statistically-degenerate best fit points at $\sin^2θ_{23} = $ 0.43 and 0.60. Results for the inverted mass hierarchy are also presented.

hep-ex↗
arXiv2015

Liquid scintillator production for the NOvA experiment

The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.

physics.ins-det↗
arXiv2012

Fundamental Physics at the Intensity Frontier

The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms.

hep-ex↗
arXiv2006

First Observation of psi(3770) --> gamma chi_{c1} --> gamma gamma J/psi

From e+e- collision data acquired with the CLEO detector at CESR, we observe the non-D Dbar decay psi(3770)->gamma chi_c1 with a statistical significance of 6.6 standard deviations, using the two-photon cascades to J/psi and J/psi->l+l-. We determine sigma(e+e- -> psi(3770)) x BR(psi(3770)->gamma chi_c1) =(18.0 pm3.3 pm2.5) pb and branching fraction BR(psi(3770)->gamma chi_c1)=(2.8+-0.5+-0.4) x 10^-3. We set 90% C.L. upper limits for the transition to chi_c2 (chi_c0) : sigma x BR < 5.7 pb (< 282 pb) and BR < 0.9 x 10^-3 (<44 x 10^-3). We also determine Gamma(psi(3770)->gamma chi_c1)/Gamma(psi(3770)->pi+pi-J/psi) =1.5+-0.3+-0.3 (>1.0 at 90 % C.L.), which bears upon the interpretation of X(3872).

hep-ex↗
arXiv2006

Charmonium Decays of $Y(4260), psi(4160), and psi(4040)

Using data collected with the CLEO detector operating at the CESR e+e- collider at sqrt s = 3.97-4.26 GeV, we investigate 15 charmonium decay modes of the psi(4040), psi(4160), and Y(4260) resonances. We confirm, at 11$σ$ significance, the BaBar Y(4260) --> pi+ pi- J/psi discovery, make the first observation of Y(4260) --> pi0 pi0 J/psi (5.1 sigma), and find the first evidence for Y(4260) --> K+ K- J/psi (3.7 sigma). We measure e+e- cross-sections at sqrt s = 4.26 GeV as sigma(pi+ pi- J/psi) = 58 +12-10 +- 4 pb, sigma(pi0 pi0 J/psi) = 23 +12 -8 +- 1 pb, and sigma(K+ K- J/psi) = 9 +9 -5 +- 1 pb, in which the uncertainties are statistical and systematic, respectively. Upper limits are placed on other decay rates from all three resonances.

hep-ex↗
arXiv2005

The Cleo Rich Detector

We describe the design, construction and performance of a Ring Imaging Cherenkov Detector (RICH) constructed to identify charged particles in the CLEO experiment. Cherenkov radiation occurs in LiF crystals, both planar and ones with a novel ``sawtooth''-shaped exit surface. Photons in the wavelength interval 135--165 nm are detected using multi-wire chambers filled with a mixture of methane gas and triethylamine vapor. Excellent pion/kaon separation is demonstrated.

physics.ins-det↗
arXiv2005

Absolute Branching Fraction Measurements of Exclusive D^0 Semileptonic Decays

With the first data sample collected by the CLEO-c detector at the psi(3770) resonance we have studied four exclusive semileptonic decays of the D0 meson. Our results include the first observation and absolute branching fraction measurement for D0 --> rho- e+ nu_e and improved measurements of the absolute branching fractions for D0 decays to K- e+ nu_e, pi- e+ nu_e, and K*- e+ nu_e.

hep-ex↗
arXiv2004

Wess-Zumino Current and the Structure of the Decay tau^- to K^-K^+ pi^- nu_tau

We present the first study of the vector (Wess-Zumino) current in tau^-\to K^-pi^-K^+ν_τdecay using data collected with the CLEO III detector at the Cornell Electron Storage Ring. We determine the quantitative contributions to the decay width from the vector and axial vector currents. Within the framework of a model by Kuhn and Mirkes, we identify the quantitative contributions to the total decay rate from the intermediate states ωπ, ρ^{(\prime)}πand K^{*}K.

hep-ex↗
arXiv2003

First Search for the Flavor Changing Neutral Current Decay D^0 -> gamma gamma

Using 13.8 fb^{-1} of data collected at or just below the Υ(4S) with the CLEO detector, we report the result of a search for the flavor changing neutral current process D^{0} \to γγ. We observe no significant signal for this decay mode and determine 90% confidence level upper limits on the branching fractions Br(D^{0}\to γγ)/Br(D^{0}\toπ^{0}π^{0}) < 0.033 and Br(D^{0}\toγγ) < 2.9 \times 10^{-5}.''

hep-ex↗
arXiv2002

Observation of $\bar{B}^0\to D^0π^0$ and $\bar{B}^0\to D^{*0}π^0$

We have studied the color-suppressed hadronic decays of neutral B mesons into the final states D(*)0 pi0. Using 9.67 million B-pairs collected with the CLEO detector, we observe the decays B0bar -> D0 pi0 and B0bar -> D*0 pi0 with the branching fractions BR(B0bar -> D0 pi0) = (2.74 -0.32 +0.36 +-0.55) 10^{-4} and BR(B0bar -> D*0 pi0) = (2.20 -0.52 +0.59 +-0.79) 10^{-4}. The first error is statistical and the second systematic. The statistical significance of the D0 pi0 signal is 12.1 sigma (5.9 sigma for D*0 pi0). Utilizing the B0bar -> D(*)0 pi0 branching fractions we determine the strong phases delta_I between isospin 1/2 and 3/2 amplitudes in the D pi and D* pi final states to be cos delta_I = 0.89 +- 0.08 and cos delta_I = 0.89 +- 0.08, respectively.

hep-ex↗
arXiv2001

Bounds on the CP Asymmetry in $b\to sγ$ Decays

We have measured the CP asymmetry A_CP = [BF(b -> s gamma) - BF(bbar -> sbar gamma)]/ [BF(b -> s gamma) + BF(bbar -> sbar gamma)] to be A_CP = (-0.079 +/- 0.108 +/- 0.022)(1.0 +/- 0.030), implying that, at 90% confidence level, A_CP lies between -0.27 and +0.10. These limits rule out some extreme non-Standard Model predictions, but are consistent with most, as well as with the Standard Model.

hep-ex↗
arXiv2001

First Measurement of $Γ(D^{*+})$

We have made the first measurement of the D*+ width using 9/fb of e+e- data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the D*+ -> D0 pi+ decay. Our preliminary result is Gamma(D*+) = 96 +- 4 (Statistical) +- 22 (Systematic) keV.

hep-ex↗
arXiv2000

Radiative B Decays at CLEO

We report on the status of a variety of radiative B decays studied by the CLEO detector with $9.7\times 10^6$ $B\bar{B}$ pairs.

hep-ph↗
arXiv1999

Measurement of Charge Asymmetries in Charmless Hadronic B Decay

We search for CP violating asymmetries in five charmless hadronic B meson decays using the full CLEO II and CLEO II.V data samples totalling 9.7 million BBbar events. The resulting Acp measurements have a precision that varies from +-0.12 to +-0.25 (absolute) depending on mode. No significant nonzero asymmetry is observed in any mode but 90% CL limits are strong and rule out some estimates of Acp.

hep-ex↗
arXiv1998

Search for Exclusive Rare Baryonic Decays of $B$ Mesons

We report the results of a search for the rare baryonic decay modes B -> Lambda Lambdabar, B -> Lambdabar p, B -> Lambdabar p pi, and B -> p pbar using 5.8M BBbar pairs collected with the CLEO detector. We see no statistically significant signals in any of these modes and set 90% confidence level upper limits on their branching fractions, B(B -> Lambda Lambdabar) < 3.9 \times 10^{-6}, B(B -> Lambdabar p) < 2.6 \times 10^{-6}, B(B -> Lambdabar p pi) < 1.3 \times 10^{-5}, and B(B -> p pbar) < 7.0 \times 10^{-6}.

hep-ex↗