arXiv subjects

D. Cronin-Hennessy

Publications and source records attributed to D. Cronin-Hennessy.

143 records · Page 8Linked to original sources

arXiv2010

Search for rare and forbidden decays of charm and charmed-strange mesons to final states h^+- e^-+ e^+

We have searched for flavor-changing neutral current decays and lepton-number-violating decays of D^+ and D^+_s mesons to final states of the form h^+- e^-+ e^+, where h is either πor K. We use the complete samples of CLEO-c open-charm data, corresponding to integrated luminosities of 818 pb^-1 at the center-of-mass energy E_CM = 3.774 GeV containing 2.4 x 10^6 D^+D^- pairs and 602 pb^-1 at E_CM = 4.170 GeV containing 0.6 x 10^6 D^*+-_s D^-+_s pairs. No signal is observed in any channel, and we obtain 90% confidence level upper limits on branching fractions B(D^+ --> π^+ e^+ e^-) < 5.9 x 10^-6, B(D^+ --> π^- e^+ e^+) < 1.1 x 10^-6, B(D^+ --> K^+ e^+ e^-) < 3.0 x 10^-6, B(D^+ --> K^- e^+ e^+) < 3.5 x 10^-6, B(D^+_s --> π^+ e^+ e^-) < 2.2 x 10^-5, B(D^+_s --> π^- e^+ e^+) < 1.8 x 10^-5, B(D^+_s --> K^+ e^+ e^-) < 5.2 x 10^-5, and B(D^+_s --> K^- e^+ e^+) < 1.7 x 10^-5.

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arXiv2010

Study of psi(2S) Decays to gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} and Search for p bar{p} Threshold Enhancements

The decays of psi(2S) into gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} have been studied with the CLEO-c detector using a sample of 24.5 million psi(2S) events obtained from e^+e^- annihilations at sqrt{s} = 3686 MeV. The data show evidence for the excitation of several N^* resonances in p pi^0 and p eta channels in pi^0 p bar{p} and eta p bar{p} decays, and f_2 states in gamma p bar{p} decay. Branching fractions for decays of psi(2S) to gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} have been determined. No evidence for p bar{p} threshold enhancements was found in the reactions psi(2S)-> X p bar{p}, where X = gamma, pi^0, eta. We do, however, find confirming evidence for a p bar{p} threshold enhancement in J/psi-> gamma p bar{p} as previously reported by BES.

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arXiv2010

A Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector

We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the Standard-Model Extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of $20-510$ over the current best limits found using the MINOS near detector.

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arXiv2010

Branching fractions for chi_cJ -> p p-bar pi^0, p p-bar eta, and p p-bar omega

Using a sample of 25.9 million psi(2S) decays acquired with the CLEO-c detector at the CESR e^+e^- collider, we report branching fractions for the decays chi_cJ -> p p-bar pi^0, p p-bar eta, and p p-bar omega, with J=0,1,2. Our results for B(chi_cJ-> p p-bar pi^0) and B(chi_cJ-> p p-bar eta) are consistent with, but more precise than, previous measurements. Furthermore, we include the first measurement of B(chi_cJ-> p p-bar omega).

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arXiv2010

Analysis of D+ to K- pi+ e+ nu_e and D+ to K- pi+ mu+ nu_mu Semileptonic Decays

Using a large sample (~11800 events) of D^+ into K^- pi^+ e^+ nu_e and D^+ into K^- pi^+ mu^+ nu_mu decays collected by the CLEO-c detector running at the psi(3770), we measure the helicity basis form factors free from the assumptions of spectroscopic pole dominance and provide new, accurate measurements of the absolute branching fractions for D^+ into K^- pi^+ e^+ nu_e and D^+ into K^- pi^+ mu^+ nu_mu decays. We find branching fractions which are consistent with previous world averages. Our measured helicity basis form factors are consistent with the spectroscopic pole dominance predictions for the three main helicity basis form factors describing D^+ into anti-K*0 ell^+ nu_mu decay. The ability to analyze D^+ into K^- pi^+ mu^+ nu_mu allows us to make the first non-parametric measurements of the mass-suppressed form factor. Our result is inconsistent with existing Lattice QCD calculations. Finally, we measure the form factor that controls non-resonant s-wave interference with the D^+ into anti-K*0 ell^+ nu_mu amplitude and search for evidence of possible additional non-resonant d-wave or f-wave interference with the anti-K*0.

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arXiv2010

Search for psi(2S) -> gamma eta_c(2S) via fully reconstructed eta_c(2S) decays

We report a search for the decay psi(2S) -> gamma eta_c(2S) in a sample of 25.9 million psi(2S) events collected with the CLEO-c detector. No signals are observed in any of the 11 exclusive eta_c(2S) decay modes studied, or in their sum. Product branching fraction upper limits are determined as a function of Gamma[eta_c(2S)] for the 11 individual modes.

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arXiv2010

Measurement of the eta_b(1S) mass and the branching fraction for Upsilon(3S) --> gamma eta_b(1S)

We report evidence for the ground state of bottomonium, eta_b(1S), in the radiative decay Upsilon(3S) --> gamma eta_b in e^+e^- annihilation data taken with the CLEO III detector. Using 6 million Upsilon(3S) decays, and assuming Gamma(eta_b) = 10 MeV/c^2, we obtain B(Upsilon(3S) --> gamma eta_b) = (7.1 +- 1.8 +- 1.1) X 10^{-4}, where the first error is statistical and the second is systematic. The statistical significance is about 4 sigma. The mass is determined to be M(eta_b) = 9391.8 +- 6.6 +- 2.0 MeV/c^2, which corresponds to the hyperfine splitting Delta M_{hf}(1S)_b = 68.5 +- 6.6 +- 2.0 MeV/c^2. Using 9 million Upsilon(2S) decays, we place an upper limit on the corresponding Y(2S) decay, B(Y(2S) --> gamma eta_b) < 8.4 X 10^{-4} at 90 % confidence level.

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arXiv2008

Measurement of Charm Production Cross Sections in e+e- Annihilation at Energies between 3.97 and 4.26 GeV

Using the CLEO-c detector at the Cornell Electron Storage Ring, we have measured inclusive and exclusive cross sections for the production of D+, D0 and Ds+ mesons in e+e- annihilations at thirteen center-of-mass energies between 3.97 and 4.26 GeV. Exclusive cross sections are presented for final states consisting of two charm mesons (DD, D*D, D*D*, Ds+Ds-, Ds*+Ds-, and Ds*+Ds*-) and for processes in which the charm-meson pair is accompanied by a pion. No enhancement in any final state is observed at the energy of the Y(4260).

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arXiv2007

A Study of the Decays D^0 --> pi^- e^+ nu_e, D^0 --> K^- e^+ nu_e, D^+ --> pi^0 e^+ nu_e, and D^+ --> barK^0 e^+ nu_e

Using 1.8 million DDbar pairs and a neutrino reconstruction technique, we have studied the decays D^0 -> K^- e^+ nu_e, D^0 -> pi^- e^+ nu_e, D^+ -> Kbar^0 e^+ nu_e, and D^+ -> pi^0 e^+ nu_e. We find B(D^0 -> pi^- e^+ nu_e) = 0.299(11)(9)%, B(D^+ -> pi^0 e^+ nu_e) = 0.373(22)(13)%, B(D^0 -> K^- e^+ nu_e) = 3.56(3)(9)%, and B(D^+ -> Kbar^0 e^+ nu_e) = 8.53(13)(23)%. In addition, form factors are studied through fits to the partial branching fractions obtained in five q^2 ranges. By combining our results with recent unquenched lattice calculations, we obtain |Vcd| = 0.217(9)(4)(23) and |Vcs| = 1.015(10)(11)(106).

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arXiv2007

Study of Di-Pion Transitions Among Upsilon(3S), Upsilon(2S), and Upsilon(1S) States

We present measurements of decay matrix elements for hadronic transitions of the form Upsilon(nS) -> pi pi Upsilon(mS) where (n, m) = (3, 1), (2, 1), and (3, 2). We reconstruct charged and neutral pion modes with the final state Upsilon decaying to either mu+mu- or e+e-. Dalitz plot distributions for the twelve decay modes are fit individually as well as jointly assuming isospin symmetry, thereby measuring the matrix elements of the decay amplitude. We observe and account for the anomaly previously noted in the di-pion invariant mass distribution for the Upsilon(3S) -> pi pi Upsilon(1S) transition and obtain good descriptions of the dynamics of the decay using the most general decay amplitude allowed by partial conservation of the axial-vector current (PCAC) considerations. The fits further indicate that the Upsilon(2S) -> pi pi Upsilon(1S) and Upsilon(3S) -> pi pi Upsilon(2S) transitions also show the presence of terms in the decay amplitude that were previously ignored, although at a relatively suppressed level.

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arXiv2006

Search for the non-D\barD Decay psi(3770) --> K_S^0 K_L^0

Using the current world's largest data sample of psi(3770) decays, we present results of a search for the non-DDbar decay psi(3770) -> KsKl. We find no signal, and obtain an upper limit of Sigma(psi(3770) -> KsKl) < 0.07 pb at 90% confidence level (CL). Our result tests a theoretical prediction for the upper bound on B(psi(3770) -> KsKl) based on a charmonia-mixing model.

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arXiv2005

Searches for CP Violation and ππS-Wave in the Dalitz-Plot Analysis of D0 --> π+π-\pi0

In e+e- collisions recorded using the CLEO II.V detector we have studied the Cabibbo suppressed decay of D0 -> pi+pi-pi0 with the initial flavor of the D0 tagged by the decay D*+ -> D0pi+. We use the Dalitz-plot analysis technique to measure the resonant substructure in this final state and observe ρπand non-resonant contributions by fitting for their amplitudes and relative phases. We describe the pipi S-wave with a K-matrix formalism and limit this contribution to the rate to be < 2.5% @95% confidence level, in contrast to the large rate observed in D+ -> pi+pi-pi+ decay. Using the amplitudes and phases from this analysis, we calculate an integrated CP asymmetry of 0.01^{+0.09}_{-0.07} +/- 0.05.

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arXiv2003

Observation of the Hadronic Transitions chi_b1,2 (2P) --> omega Upsilon(1S)

The CLEO Collaboration has made the first observations of hadronic transitions among bottomonium (b-bbar) states other than the dipion transitions among upsns states. In our study of Y(3S) decays, we find a significant signal for Y(3S) -> gamma omega Y(1S) that is consistent with radiative decays Y(3S) -> gamma chi_b1,2(2P), followed by chi_b1,2(2P) -> omega Y(1S). The branching ratios we obtain are B(chi_b1(2P) -> omega Y(1S)) = (1.63 +0.35-0.31 +0.16-0.15)% and B(chi_b2(2P) -> omega Y(1S)) = (1.10 +0.32-0.28 +0.11-0.10)%, in which the first error is statistical and the second is systematic.

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arXiv2002

First Observation of the Exclusive Decays Lambda_c to Lambda pi+pi+pi-pi0 and Lambda_c to Lambda omega pi+

Using data recorded by the CLEO III detector at CESR, we report on the first measurements of the branching fractions for decays of the Lambda_c^+ charmed baryon into (Lambda pi+ pi+ pi- pi0) and (Lambda omega pi+). All rates are measured with respect to the p K- pi+ decay mode. The relative branching fractions are 0.39 +- 0.09(stat.) +- 0.09(syst.) and 0.24 +- 0.06(stat.) +- 0.06(syst.) for the (Lambda pi+ pi+ pi- pi0) and (Lambda omega pi+) modes, respectively. The data also suggest decays of the Lambda_c^+ via (Lambda eta pi+, eta --> pi+ pi- pi0) with a rate which is consistent with previous measurements of the branching fraction of Lambda_c^+ to (Lambda eta pi+, eta --> gamma gamma). The measurements indicate that the omega and eta sub-modes comprise 87+-13% of the (Lambda pi+ pi+ pi- pi0) final state. We set an upper limit on the contribution from non-omega and non-eta modes of 0.13 at the 90% confidence level.

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arXiv2001

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 = 0.251 +- 0.066 GeV^2, < (M_X^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.

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arXiv2001

Mixing and CP Violation in the Decay of Neutral D Mesons at CLEO

We present preliminary results of several analyses searching for the effects of CP violation and mixing in the decay of D0 mesons. We find no evidence of CP asymmetry in five different two-body decay modes of the D0 to pairs of light pseudo-scalar mesons: A_CP(K+ K-) = (+0.05 +- 2.18 +- 0.84)%, A_CP(pi+ pi-) = (+2.0 +- 3.2 +- 0.8)%, A_CP(K0_S pi0) = (+0.1 +- 1.3)%, A_CP(pi0 pi0) = (+0.1 +- 4.8)% and A_CP(K0_S K0_S) = (-23 +- 19)%. We present the first measurement of the rate of wrong-sign D0 -> K+ pi- pi0 decay: R_WS = 0.0043 + 0.0011 - 0.0010 +- 0.0007. Finally, we describe a measurement of the mixing parameter y_CP= Delta Gamma / (2 Gamma) by searching for a lifetime difference between the CP neutral K+ pi- final state and the CP even K+K- and pi+pi- final states. Under the assumption that CP is conserved we find y_CP = -0.011 +- 0.025 +- 0.014.

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arXiv2000

Observation of the $Ω_{c}^{0}$ 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 $Ω_c^0$ (css-ground state) in $e^{+}e^{-}$ collisions at $\sqrt{s} \simeq 10.6$ {\rm GeV}. The modes used to study the $Ω_c^0$ are $Ω^- π^+$, $Ω^- π^+ π^0$, $Ξ^- K^- pi^+ π^+$, $Ξ^0 K^- pi^+$, and $Ω^- π^+ π^- π^+$. 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.

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