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1. Search for Rare and Forbidden Charm Meson DecaysD0→Vℓ+ℓ−andhhℓℓ

Author

K. O'Shaughnessy, dos Reis Ac, K. C. Peng, A. K. Tripathi, S. M. Yang, N. R. Stanton, Alberto Santoro, A. J. Slaughter, A. Nguyen, P.A. Kasper, S. Yoshida, A. Napier, K. Denisenko, S. B. Bracker, A. Álvarez Fernández, M. Sheaff, S. Amato, D. Yi, D. C. Langs, R. Weiss-Babai, R. A. Burnstein, L. M. Cremaldi, E. Wolin, G. F. Fox, B. Quinn, A.B. d'Oliveira, A. Rafatian, E.M. Aitala, C. James, N. W. Reay, J. Leslie, N. Witchey, S. Takach, G. Hurvits, C. Zhang, S. Watanabe, de Mello Neto, M. V. Purohit, B. Lundberg, R. H. Milburn, H.S. Carvalho, A.K.S. Santha, A.M. Halling, S. Banerjee, Kevin Stenson, J. C. Anjos, J. A. Appel, R. A. Sidwell, J. Magnin, Sokoloff, R. Zaliznyak, D. J. Summers, K. Gounder, Daniel Ashery, T. Carter, A. J. Schwartz, D. A. Sanders, L. Perera, G. Blaylock, G. Herrera, K. Thorne, Simon Kwan, D. Mihalcea, S. Devmal, H. A. Rubin, S. Radeztsky, P. Gagnon, C. L. Darling, R. J. Stefanski, N. K. Copty, J. Solano, J. Wiener, J.J. Reidy, C. Göbel, S. MayTal-Beck, de Miranda Jm, B. T. Meadows, P. R. Burchat, and I. Bediaga

Subjects
Physics, Particle physics, Antiparticle, Muon, Meson, Neutral current, High Energy Physics::Phenomenology, General Physics and Astronomy, Nuclear physics, Pseudoscalar, High Energy Physics::Experiment, Vector meson, Charm (quantum number), Lepton
Abstract

We report results of a search for flavor-changing neutral current (FCNC), lepton flavor, and lepton-number violating decays of the ${D}^{0}$ (and its antiparticle) into three and four bodies. Using data from Fermilab charm hadroproduction experiment E791, we examine modes with two leptons (muons or electrons) and a ${\ensuremath{\rho}}^{0}$, ${\overline{K}}^{*0}$, or $\ensuremath{\varphi}$ vector meson or a nonresonant $\ensuremath{\pi}\ensuremath{\pi}$, $K\ensuremath{\pi}$, or $\mathrm{KK}$ pair of pseudoscalar mesons. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 27 decay modes examined (18 new).

Published
2001
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2. Study of theDs+→π−π+π+Decay and Measurement off0Masses and Widths

Author

G. F. Fox, D. J. Summers, K. Gounder, J. M. De Miranda, B. T. Meadows, M. D. Sokoloff, J. R. T. de Mello Neto, P.A. Kasper, S. B. Bracker, S. Radeztsky, S. Watanabe, J.J. Reidy, M. Sheaff, R. J. Stefanski, S. Devmal, R. A. Sidwell, S. Takach, B. Lundberg, I. Bediaga, C. Zhang, A. J. Slaughter, J. A. Appel, A. Napier, Daniel Ashery, K. Denisenko, P. Gagnon, A.M. Halling, D. Yi, K. C. Peng, H.S. Carvalho, S. M. Yang, A. Nguyen, A. Massafferri, H. A. Rubin, N. K. Copty, S. MayTal-Beck, R. Zaliznyak, Simon Kwan, S. Yoshida, A. K. Tripathi, D. C. Langs, M. V. Purohit, C. L. Darling, K. O'Shaughnessy, G. Blaylock, A.K.S. Santha, J. Solano, C. James, S. Amato, A.B. d'Oliveira, E.M. Aitala, Alberto Santoro, J. C. Anjos, N. W. Reay, J. Leslie, J. Magnin, D. A. Sanders, J. Wiener, L. Perera, D. Mihalcea, A. C. dos Reis, R. Weiss-Babai, A. Álvarez Fernández, L. M. Cremaldi, K. Thorne, Patricia R. Burchat, E. Wolin, S. Banerjee, N. Witchey, C. Göbel, A. J. Schwartz, R. H. Milburn, R. A. Burnstein, N. R. Stanton, A. Rafatian, G. Hurvits, Kevin Stenson, G. Herrera, T. Carter, and B. Quinn

Subjects
Physics, Crystallography, Particle physics, Pi, General Physics and Astronomy, Dalitz plot
Abstract

From a sample of $848\ifmmode\pm\else\textpm\fi{}44$ ${D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}$ decays, we find $\ensuremath{\Gamma}({D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+})/\ensuremath{\Gamma}({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\varphi}{\ensuremath{\pi}}^{+})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.245\ifmmode\pm\else\textpm\fi{}{0.028}_{\ensuremath{-}0.012}^{+0.019}$. Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels ${\ensuremath{\rho}}^{0}(770){\ensuremath{\pi}}^{+}$, ${\ensuremath{\rho}}^{0}(1450){\ensuremath{\pi}}^{+}$, ${f}_{0}(980){\ensuremath{\pi}}^{+}$, ${f}_{2}(1270){\ensuremath{\pi}}^{+}$, and ${f}_{0}(1370){\ensuremath{\pi}}^{+}$. We also present the values obtained for masses and widths of the resonances ${f}_{0}(980)$ and ${f}_{0}(1370)$.

Published
2001
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3. Experimental Evidence for a Light and Broad Scalar Resonance inD+→π−π+π+Decay

Author

N. R. Stanton, N. Witchey, D.C. Langs, S. Radeztsky, S. MayTal-Beck, A. Nguyen, Alberto Santoro, Kevin Stenson, J. Magnin, A.K. Tripathi, A.M. Halling, D. J. Summers, K. Gounder, R. H. Milburn, I. Bediaga, C. Zhang, R. A. Burnstein, J. A. Appel, G. F. Fox, S. M. Yang, S. Yoshida, P.A. Kasper, J.J. Reidy, A. Massafferri, A. Rafatian, J. Wiener, R. J. Stefanski, G. Blaylock, A. Napier, H.S. Carvalho, B. Lundberg, de Miranda Jm, K. Denisenko, D. Yi, Sokoloff, N. W. Reay, J. Leslie, G. Hurvits, C. Göbel, S. Takach, S. Watanabe, R. Weiss-Babai, B. T. Meadows, Daniel Ashery, M. Sheaff, C. L. Darling, S. B. Bracker, D. A. Sanders, A. J. Schwartz, Simon Kwan, Sudeshna Banerjee, J. C. Anjos, T. Carter, G. Herrera, P. Gagnon, C. James, R. Zaliznyak, N. K. Copty, S. Amato, B. Quinn, H. A. Rubin, de Mello Neto, J. Solano, D. Mihalcea, A. J. Slaughter, M. V. Purohit, A.K.S. Santha, K. O'Shaughnessy, dos Reis Ac, S. Devmal, L.P. Perera, R. A. Sidwell, Patricia R. Burchat, A.B. d'Oliveira, E.M. Aitala, A. Álvarez Fernández, L. M. Cremaldi, E. Wolin, K. C. Peng, and K. Thorne

Subjects
Physics, Nuclear magnetic resonance, Amplitude, Scalar (mathematics), Analytical chemistry, Pi, General Physics and Astronomy, Dalitz plot, Resonance
Abstract

From a sample of 1172 +/- 61 D(+)-->pi(-)pi(+)pi(+) decays, we find gamma(D(+)-->pi(-)pi(+)pi(+))/gamma(D(+)-->K-pi(+)pi(+)) = 0.0311 +/- 0.0018(+0.0016)(-0.0026). Using a coherent amplitude analysis to fit the Dalitz plot of these decays, we find strong evidence that a scalar resonance of mass 478(+24)(-23) +/- 17 MeV/c(2) and width 324(+42)(-40) +/- 21 MeV/c(2) accounts for approximately half of all decays.

Published
2001
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4. Asymmetries in the production of Λc+ and Λc− baryons in 500 GeV/c π− nucleon interactions

Author

S. M. Yang, R. A. Burnstein, Kevin Stenson, S. Yoshida, A. Rafatian, C. Zhang, H.S. Carvalho, N. Witchey, M. V. Purohit, A. Nguyen, K. C. Peng, A.B. d'Oliveira, A. Fernandez, D.C. Langs, S. MayTal-Beck, B. Quinn, J. R. T. de Mello Neto, A.K.S. Santha, E.M. Aitala, A. Napier, K. Denisenko, D. Yi, R. Weiss-Babai, G. Hurvits, R. A. Sidwell, D. A. Sanders, R. J. Stefanski, N. K. Copty, A.K. Tripathi, I. Bediaga, G. Blaylock, K. Thorne, J. C. Anjos, A. J. Slaughter, T. Carter, L. M. Cremaldi, E. Wolin, D. Mihalcea, S. B. Bracker, N. R. Stanton, F.R.A. Simão, A. C. dos Reis, J. Magnin, A. J. Schwartz, C. L. Darling, J.J. Reidy, B. Lundberg, B. T. Meadows, R. Zaliznyak, M. Sheaff, M. D. Sokoloff, G. Herrera, P.A. Kasper, Sudeshna Banerjee, S. Devmal, P. R. Burchat, D. J. Summers, R. H. Milburn, L.P. Perera, K. Gounder, K. O'Shaughnessy, J. M. De Miranda, Alberto Santoro, J. Solano, Daniel Ashery, S. Amato, G. F. Fox, H. A. Rubin, S. Takach, S. Radeztsky, S. Watanabe, A.M. Halling, Simon Kwan, P. Gagnon, C. James, J. A. Appel, N. W. Reay, J. Leslie, J. Wiener, and C. Göbel

Subjects
Physics, Nuclear and High Energy Physics, media_common.quotation_subject, Lambda, Asymmetry, Baryon, Nuclear physics, symbols.namesake, Pi, symbols, Feynman diagram, Production (computer science), Fermilab, Nucleon, media_common
Abstract

We present a measurement of asymmetries in the production of Λ c + and Λ c − baryons in 500 GeV/ c π − -nucleon interactions from the E791 experiment at Fermilab. The asymmetries were measured as functions of Feynman x ( x F ) and transverse momentum squared ( p T 2 ) using a sample of 1 819±62 Λ c 's observed in the decay channel Λ c + → pK − π + . We observe more Λ c + than Λ c − baryons, with an asymmetry of (12.7±3.4±1.3)% independent of x F and p T 2 in our kinematical range (−0.1⩽ x F ⩽0.6 and 0.0⩽ p T 2 ⩽8.0 (GeV/ c ) 2 ). This Λ c asymmetry measurement is the first with data in both the positive and negative x F regions.

Published
2000
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5. Asymmetries in the production of Λ0, Ξ−, and hyperons in 500 GeV/c π−–nucleon interactions

Author

J. A. Appel, Michael Sokoloff, K. O'Shaughnessy, A. Napier, P.A. Kasper, A.B. d'Oliveira, E.M. Aitala, K. Denisenko, D. Yi, R. Weiss-Babai, C. James, R. Zaliznyak, S. Devmal, B. Quinn, G. Blaylock, A.J. Slaughter, A. J. Schwartz, C. L. Darling, S. Takach, A. Rafatian, L.P. Perera, K. C. Peng, S. B. Bracker, N. Witchey, J. R. T. de Mello Neto, J. Wiener, J.J. Reidy, G. Hurvits, Milind Purohit, I. Bediaga, Don Summers, A. Fernandez, D.C. Langs, R. A. Sidwell, B. Lundberg, C. Göbel, C. Zhang, A.K.S. Santha, L. M. Cremaldi, D. Ashery, E. Wolin, A. Nguyen, S. MayTal-Beck, H. A. Rubin, Kevin Stenson, M. Sheaff, N. R. Stanton, J. C. Anjos, T. Carter, A.K. Tripathi, R. H. Milburn, Alberto Santoro, F.R.A. Simão, N. K. Copty, Brian Meadows, Patricia R. Burchat, A. C. dos Reis, K. Thorne, J. Solano, G. Herrera, S. Yoshida, H.S. Carvalho, N. W. Reay, J. Leslie, Simon Kwan, David Sanders, P. Gagnon, K. Gounder, J. M. De Miranda, S. Radeztsky, A.M. Halling, J. Magnin, R.A. Burnstein, Sudeshna Banerjee, S. Amato, G. F. Fox, and S. Watanabe

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, Astrophysics::Cosmology and Extragalactic Astrophysics, Asymmetry, Nuclear physics, Baryon, symbols.namesake, Transverse momentum, symbols, Feynman diagram, High Energy Physics::Experiment, Fermilab, Nuclear Experiment, Nucleon, media_common
Abstract

We present a measurement of asymmetries in the production of Λc+ and Λc− baryons in 500 GeV/c π−-nucleon interactions from the E791 experiment at Fermilab. The asymmetries were measured as functions of Feynman x (xF) and transverse momentum squared (pT2) using a sample of 1 819±62 Λc's observed in the decay channel Λc+→pK−π+. We observe more Λc+ than Λc− baryons, with an asymmetry of (12.7±3.4±1.3)% independent of xF and pT2 in our kinematical range (−0.1⩽xF⩽0.6 and 0.0⩽pT2⩽8.0 (GeV/c)2). This Λc asymmetry measurement is the first with data in both the positive and negative xF regions.

Published
2000
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6. Correlations between D and $${\overline D}$$ mesons produced in 500 GeV/cπ−-nucleon interactions

Author

D. Ashery, Patricia R. Burchat, S. Radeztsky, K. O'Shaughnessy, J. A. Appel, J.J. Reidy, H.S. Carvalho, A.M. Halling, K. Gounder, J. M. De Miranda, B. Lundberg, A.B. d'Oliveira, David Sanders, C. Göbel, E.M. Aitala, K. C. Peng, Kevin Stenson, G. Blaylock, Don Summers, C.J. Solano Salinas, L.P. Perera, R.A. Burnstein, K. Thorne, S. Takach, Milind Purohit, I. Bediaga, Sudeshna Banerjee, S. MayTal-Beck, L. M. Cremaldi, E. Wolin, J. R. T. de Mello Neto, A.K.S. Santha, A. Napier, K. Denisenko, S. Amato, D. Yi, A.J. Slaughter, A.K. Tripathi, R. Weiss-Babai, G. F. Fox, J. C. Anjos, H. A. Rubin, D. Mihalcea, R. A. Sidwell, S. Watanabe, A. Nguyen, B. Quinn, S. M. Yang, C. Zhang, A. C. dos Reis, R. J. Stefanski, S. Yoshida, T. Carter, N. Witchey, A. Fernandez, D.C. Langs, M. Sheaff, Sokoloff, N. K. Copty, N. R. Stanton, C. James, Stephen B. Bracker, J. Wiener, R. Zaliznyak, P.A. Kasper, Simon Kwan, P. Gagnon, N. W. Reay, J. Leslie, C. L. Darling, A. Rafatian, G. Hurvits, Alberto Santoro, Brian Meadows, R. H. Milburn, A. J. Schwartz, and G. Herrera

Subjects
Physics, Quantum chromodynamics, Particle physics, Meson, High Energy Physics::Phenomenology, Order (ring theory), Nuclear physics, D meson, High Energy Physics::Experiment, Production (computer science), Charm (quantum number), Nuclear Experiment, Nucleon, Event generator
Abstract

We present a study of correlations between D and $${\overline D}$$ mesons produced in 500 GeV/cπ−-nucleon interactions, based on data from experiment E791 at Fermilab. We have fully reconstructed 791 ± 44 charm meson pairs to study correlations between the transverse and longitudinal momenta of the two D mesons and the relative production rates for different types of D meson pairs. We see slight correlations between the longitudinal momenta of the D and the $${\bar D}$$ , and significant correlations between the azimuthal angle of the D and the $${\bar D}$$ . The experimental distributions are compared to a next-to-leading-order QCD calculation and to predictions of the PYTHIA/JETSET Monte Carlo event generator. We observe less correlation between transverse momenta and different correlations between longitudinal momenta than these models predict for the default values of the model parameters. Better agreement between data and theory might be achieved by tuning the model parameters or by adding higher order perturbative terms, thus contributing to a better understanding of charm production. The relative production rates for the four sets of charm pairs, $$D^0{{\overline D}^0}, D^0 D^{-}, D^+{{\overline D}^0}, D^+ D^{-}$$ as calculated in the PYTHIA/JETSET event generator with the default parameters, agree with data as far as the relative ordering, but predict too many $$D^+ {{\overline D}^0}$$ pairs and too few $$D^+ D^{-}$$ pairs.

Published
2000
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7. Multidimensional resonance analysis of Λc+→pK−π+

Author

E.M. Aitala, S. Amato, J.C. Anjos, J.A. Appel, D. Ashery, S. Banerjee, I. Bediaga, G. Blaylock, S.B. Bracker, P.R. Burchat, R.A. Burnstein, T. Carter, H.S. Carvalho, N.K. Copty, L.M. Cremaldi, C. Darling, K. Denisenko, S. Devmal, A. Fernandez, G.F. Fox, P. Gagnon, C. Gobel, K. Gounder, A.M. Halling, G. Herrera, G. Hurvits, C. James, P.A. Kasper, S. Kwan, D.C. Langs, J. Leslie, B. Lundberg, J. Magnin, S. MayTal-Beck, B. Meadows, J.R.T. de Mello Neto, D. Mihalcea, R.H. Milburn, J.M. de Miranda, A. Napier, A. Nguyen, A.B. d'Oliveira, K. O'Shaughnessy, K.C. Peng, L.P. Perera, M.V. Purohit, B. Quinn, S. Radeztsky, A. Rafatian, N.W. Reay, J.J. Reidy, A.C. dos Reis, H.A. Rubin, D.A. Sanders, A.K.S. Santha, A.F.S. Santoro, A.J. Schwartz, M. Sheaff, R.A. Sidwell, A.J. Slaughter, M.D. Sokoloff, J. Solano, N.R. Stanton, R.J. Stefanski, K. Stenson, D.J. Summers, S. Takach, K. Thorne, A.K. Tripathi, S. Watanabe, R. Weiss-Babai, J. Wiener, N. Witchey, E. Wolin, S.M. Yang, D. Yi, S. Yoshida, R. Zaliznyak, and C. Zhang

Subjects
Baryon, Physics, Nuclear and High Energy Physics, Particle physics, Amplitude, Resonance analysis, Pi, Resonance, Lambda, Bar (unit)
Abstract

We present the results of a five-dimensional resonant amplitude analysis of the $\Lambda_c^+{\to}pK^{-}\pi^{+}$ system based on $946\pm 38$ reconstructed decays. These data were produced in 500 GeV/$c$ $\pi^-$-N interactions by Fermilab experiment E791. We report measurements of the amplitudes for $\Lambda_c^+$ decay into nonresonant $pK^-\pi^+$ and to $p\bar{K}^{*0}(890)$, $\Delta^{++}(1232)K^-$, and $\Lambda(1520)\pi^+$ and we comment on other possible resonant enhancements. This is the first complete amplitude analysis of the $\Lambda_c^{+}{\to}pK^{-}\pi^{+}$ system. We find that $(54.8\pm5.5\pm3.5)$% of the decays are nonresonant, $(19.5\pm2.6\pm1.8)$% of the decays are via the $\bar{K}^{*0}$ resonance, $(18.0\pm2.9\pm2.9)$% of the decays are via the $\Delta^{++}$ resonance, and $(7.7\pm1.8\pm1.1)$% of the decays are via the $\Lambda(1520)$ resonance. We find evidence for an increasingly negative polarization of the $\Lambda_c^+$ baryons as a function of $p_T^2$, in agreement with a recent model\cite{dha} and with a related measurement\cite{jez}.

Published
2000
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8. Measurement of the form-factor ratios for D+s→φℓ+νℓ

Author

E.M. Aitala, S. Amato, J.C. Anjos, J.A. Appel, D. Ashery, S. Banerjee, I. Bediaga, G. Blaylock, S.B. Bracker, P.R. Burchat, R.A. Burnstein, T. Carter, H.S. Carvalho, N.K. Copty, L.M. Cremaldi, C. Darling, K. Denisenko, A. Fernandez, G.F. Fox, P. Gagnon, C. Gobel, K. Gounder, A.M. Halling, G. Herrera, G. Hurvits, C. James, P.A. Kasper, S. Kwan, D.C. Langs, J. Leslie, B. Lundberg, S. MayTal-Beck, B. Meadows, J.R.T. de Mello Neto, D. Mihalcea, R.H. Milburn, J.M. de Miranda, A. Napier, A. Nguyen, A.B. d'Oliveira, K. O'Shaughnessy, K.C. Peng, L.P. Perera, M.V. Purohit, B. Quinn, S. Radeztsky, A. Rafatian, N.W. Reay, J.J. Reidy, A.C. dos Reis, H.A. Rubin, D.A. Sanders, A.K.S. Santha, A.F.S. Santoro, A.J. Schwartz, M. Sheaff, R.A. Sidwell, A.J. Slaughter, M.D. Sokoloff, J. Solano, N.R. Stanton, R.J. Stefanski, K. Stenson, D.J. Summers, S. Takach, K. Thorne, A.K. Tripathi, S. Watanabe, R. Weiss-Babai, J. Wiener, N. Witchey, E. Wolin, S.M. Yang, D. Yi, S. Yoshida, R. Zaliznyak, and C. Zhang

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Muon, Electron channel, Form factor (quantum field theory), Lepton
Abstract

We have measured the form factor ratios r_V = V(0)/A_1(0) and r_2 = A_2(0)/A_1(0) for the decay D_s^+ -> phi ell^+ nu_ell, phi -> K^+ K^-, using data from charm hadroproduction experiment E791 at Fermilab. Results are based on 144 signal and 22 background events in the electron channel and 127 signal and 34 background events in the muon channel. We combine the measurements from both lepton channels to obtain r_V = 2.27 +- 0.35 +- 0.22 and r_2 = 1.57 +- 0.25 +- 0.19.

Published
1999
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9. Search for the pentaquark via the decay

Author

R. Zaliznyak, Sudeshna Banerjee, A. Napier, K. Denisenko, T. Carter, J.J. Reidy, D. Yi, J. A. Appel, R. Weiss-Babai, S. Takach, L.P. Perera, A. J. Schwartz, S. Amato, S. Radeztsky, Simon Kwan, G. F. Fox, P.A. Kasper, N. Witchey, S. M. Yang, L. M. Cremaldi, I. Bediaga, E. Wolin, S. MayTal-Beck, A. Fernandez, S. Yoshida, D.C. Langs, S. Gerzon, A.K. Tripathi, G. Herrera, J. Lichtenstadt, S. Watanabe, D. J. Summers, K. Gounder, P. Gagnon, J. M. De Miranda, A. J. Slaughter, B. T. Meadows, M. D. Sokoloff, P. R. Burchat, K. O'Shaughnessy, Kevin Stenson, R. A. Sidwell, R. J. Stefanski, N. W. Reay, J. Leslie, S. B. Bracker, Alberto Santoro, B. Quinn, M. V. Purohit, A.M. Halling, J. C. Anjos, H.S. Carvalho, D. Mihalcea, A.K.S. Santha, J. R. T. de Mello Neto, E.M. Aitala, K. C. Peng, Daniel Ashery, R. A. Burnstein, B. Lundberg, A. C. dos Reis, A. Rafatian, G. Hurvits, H. A. Rubin, N. K. Copty, J. Solano, J. Wiener, C. Göbel, C. Zhang, C. James, M. Sheaff, A. Nguyen, D. A. Sanders, K. Thorne, G. Blaylock, R. H. Milburn, N. R. Stanton, A. B. D'Oliveira, and C. L. Darling

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Cross section (physics), Particle physics, Branching fraction, Fermilab, Beam (structure), Pentaquark
Abstract

We have searched for evidence of the production and decay of a neutral bound-state pentaquark, one of a predicted doublet of states: P 0 c s =| c suud〉 and P − c s =| c sddu〉 . Specifically, we have searched for the decay P 0 c s →K ∗0 K − p in data from Fermilab experiment E791, in which a 500 GeV/c π− beam interacted with nuclear targets. We find mass-dependent upper limits at the 90% confidence level for the ratio of cross section times branching fraction of this decay relative to that for the decay D s − →K ∗0 K − . The upper limits vary between 0.016 and 0.036 for M(P 0 c s ) between 2.75 and 2.91 GeV/c2, assuming a pentaquark lifetime of 0.4 ps.

Published
1999
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10. Measurement of the Ds lifetime

Author

E.M. Aitala, S. Amato, J.C. Anjos, J.A. Appel, D. Ashery, S. Banerjee, I. Bediaga, G. Blaylock, S.B. Bracker, P.R. Burchat, R.A. Burnstein, T. Carter, H.S. Carvalho, N.K. Copty, L.M. Cremaldi, C. Darling, K. Denisenko, A. Fernandez, G.F. Fox, P. Gagnon, C. Gobel, K. Gounder, A.M. Halling, G. Herrera, G. Hurvits, C. James, P.A. Kasper, S. Kwan, D.C. Langs, J. Leslie, B. Lundberg, S. MayTal-Beck, B. Meadows, J.R.T. de Mello Neto, D. Mihalcea, R.H. Milburn, J.M. de Miranda, A. Napier, A. Nguyen, A.B. d'Oliveira, K. O'Shaughnessy, K.C. Peng, L.P. Perera, M.V. Purohit, B. Quinn, S. Radeztsky, A. Rafatian, N.W. Reay, J.J. Reidy, A.C. dos Reis, H.A. Rubin, D.A. Sanders, A.K.S. Santha, A.F.S. Santoro, A.J. Schwartz, M. Sheaff, R.A. Sidwell, A.J. Slaughter, M.D. Sokoloff, J. Solano, N.R. Stanton, R.J. Stefanski, K. Stenson, D.J. Summers, S. Takach, K. Thorne, A.K. Tripathi, S. Watanabe, R. Weiss-Babai, J. Wiener, N. Witchey, E. Wolin, S.M. Yang, D. Yi, S. Yoshida, R. Zaliznyak, and C. Zhang

Subjects
Physics, High Energy Physics - Experiment (hep-ex), Nuclear and High Energy Physics, Particle physics, Meson, Maximum likelihood, FOS: Physical sciences, Charm (quantum number), Fermilab, Measure (mathematics), Standard deviation, High Energy Physics - Experiment
Abstract

We report the results of a precise measurement of the Ds meson lifetime based on 1662 +/- 56 fully reconstructed Ds -> phi pi decays, from the charm hadroproduction experiment E791 at Fermilab. Using an unbinned maximum likelihood fit, we measure the Ds lifetime to be 0.518 +/- 0.014 +/- 0.007 ps. The ratio of the measured Ds lifetime to the world average D0 lifetime is 1.25 +/- 0.04. This result differs from unity by six standard deviations, indicating significantly different lifetimes for the Ds and the D0., 12 pages, 3 figures, 2 table. LaTeX

Published
1999
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11. Measurement of the form-factor ratios for D→ℓν

Author

N. R. Stanton, S. Takach, A. Napier, K. Denisenko, D. Yi, R. Weiss-Babai, B. Lundberg, S. B. Bracker, S. M. Yang, S. Radeztsky, G. Blaylock, R. Zaliznyak, K. C. Peng, S. Yoshida, J.J. Reidy, Simon Kwan, J. R. T. de Mello Neto, R. H. Milburn, A.B. d'Oliveira, E.M. Aitala, P.A. Kasper, C. Zhang, D. C. Langs, D. J. Summers, K. Gounder, B. T. Meadows, A. Álvarez Fernández, J. M. De Miranda, Kevin Stenson, M. D. Sokoloff, L. M. Cremaldi, E. Wolin, S. MayTal-Beck, S. Amato, R. J. Stefanski, Pauline Gagnon, N. K. Copty, A. J. Slaughter, T. Carter, A. Nguyen, J. Wiener, R. A. Sidwell, S. Banerjee, C. Göbel, D. Mihalcea, C. James, A.M. Halling, J. A. Appel, A. C. dos Reis, M. V. Purohit, J. Solano, G. F. Fox, B. Quinn, D. A. Sanders, Daniel Ashery, I. Bediaga, A.K.S. Santha, S. Watanabe, N. W. Reay, J. Leslie, L. Perera, N. Witchey, C. L. Darling, K. Thorne, Patricia R. Burchat, R. A. Burnstein, A. Rafatian, G. Hurvits, K. O'Shaughnessy, Alberto Santoro, M. Sheaff, H. A. Rubin, H.S. Carvalho, J. C. Anjos, A. J. Schwartz, G. Herrera, and A. K. Tripathi

Subjects
Physics, Nuclear and High Energy Physics, chemistry, Analytical chemistry, chemistry.chemical_element, Platinum, Carbon
Published
1998
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12. Search for the Pentaquark via thePcs¯0→φπpDecay

Author

S. Yoshida, S. Banerjee, A. K. Tripathi, A. J. Slaughter, S. MayTal-Beck, A. Napier, J. C. Anjos, D. Yi, R. Weiss-Babai, S. Gerzon, N. R. Stanton, J. R. T. de Mello Neto, A. Nguyen, Daniel Ashery, C. James, B. Lundberg, J. Leslie, E.M. Aitala, B. T. Meadows, D. C. Langs, M. Sheaff, M. D. Sokoloff, P. R. Burchat, N. W. Reay, S. B. Bracker, J. A. Appel, P. Gagnon, S. Amato, H. A. Rubin, K. O'Shaughnessy, J. Lichtenstadt, I. Bediaga, H.S. Carvalho, G. Blaylock, R. H. Milburn, C. Zhang, Simon Kwan, R. Zaliznyak, T. Carter, A. B. d'Oliveira, J. Wiener, P.A. Kasper, N. K. Copty, J. J. Reidy, A. J. Schwartz, K. Denisenko, S. Takach, C. Göbel, A. K. S. Santha, M. V. Purohit, R. A. Sidwell, S. Watanabe, G. Herrera, S. Radeztsky, A. C. dos Reis, C. L. Darling, D. J. Summers, K. Gounder, J. M. De Miranda, A.M. Halling, L. Perera, K. Thorne, B. Quinn, Alberto Santoro, R. A. Burnstein, A. Rafatian, G. Hurvits, Kevin Stenson, N. Witchey, K. C. Peng, A. Álvarez Fernández, L. M. Cremaldi, and E. Wolin

Subjects
Physics, Particle decay, Particle physics, Pion, Meson, Branching fraction, High Energy Physics::Phenomenology, Hadron, General Physics and Astronomy, High Energy Physics::Experiment, Energy (signal processing), Pentaquark, Bar (unit)
Abstract

We report results of the first search for the pentaquark P_{{c bar}s} which is predicted to be a doublet of states: P^0_{{c bar}s}=({c bar} s u u d) and P^-_{{c bar}s}=({c bar} s d d u). A search was made for the decay P^0_{{c bar}s} --> phi,pi,p in data from Fermilab experiment E791, in which 500 GeV/c pi^- beam interacted with nuclear targets. We present upper limits at 90% confidence level for the ratio of cross section times branching fraction of this decay to that for the decay D_s --> phi,pi. The upper limits are 0.031 and 0.063 for M(P^0_{{c bar}s}) = 2.75 and 2.86 GeV/c^2, respectively, assuming a P^0_{{c bar}s} lifetime of 0.4 ps.

Published
1998
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13. Branching fractions for D0→K+K− and D0→π+π−, and a search for CP violation in D0 decays

Author

N. Witchey, Simon Kwan, A. Fernandez, A. Nguyen, S. B. Bracker, Don Summers, P.A. Kasper, P. Gagnon, R. Zaliznyak, J. A. Appel, A. K. Tripathi, J. R. T. de Mello Neto, L.P. Perera, J.J. Reidy, A.J. Schwartz, N.J. Copty, S. Radeztsky, C. Zhang, Kevin Stenson, K. C. Peng, D. C. Langs, D. Ashery, A. Napier, R. A. Sidwell, Michael Sokoloff, K. O'Shaughnessy, K. Denisenko, A.M. Halling, S. MayTal-Beck, D. Yi, Alberto Santoro, S. Takach, A.B. d'Oliveira, R. Weiss-Babai, E.M. Aitala, T. Carter, Brian Meadows, C. L. Darling, M. Sheaff, G. Blaylock, Patricia R. Burchat, N. W. Reay, J. Leslie, A.K.S. Santha, K. Thorne, L. M. Cremaldi, E. Wolin, A. Rafatian, R.A. Burnstein, J. C. Anjos, Sudeshna Banerjee, David Sanders, G. Hurvits, J. Solano, S. Amato, K. Gounder, G. F. Fox, J. M. De Miranda, Milind Purohit, I. Bediaga, R. H. Milburn, S. Watanabe, B. Quinn, H. A. Rubin, J. Wiener, B. Lundberg, C. Göbel, C. James, G. Herrera, N. R. Stanton, H.S. Carvalho, A.J. Slaughter, S. Yoshida, and A. C. dos Reis

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, CP violation, Fermilab, Charm (quantum number), Branching (polymer chemistry), Asymmetry, High Energy Physics - Experiment, media_common
Abstract

Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we have measured ratios of branching fractions for the two-body singly-Cabibbo-suppressed charged decays of the D0: (D0 -> KK)/(D0 -> Kpi) = 0.109 +- 0.003 +- 0.003, (D0 -> pipi)/(D0 -> Kpi) = 0.040 +- 0.002 +- 0.003, and (D0 -> KK)/(D0 -> pipi) = 2.75 +- 0.15 +- 0.16. We have looked for differences in the decay rates of D0 and D0bar to the CP eigenstates K+K- and pi+pi-, and have measured the CP asymmetry parameters A_CP(K+K-) = -0.010 +- 0.049 +- 0.012 and A_CP(pi+pi-) = -0.049 +- 0.078 +- 0.030, both consistent with zero., Comment: 10 Postscript pages, including 2 figures. Submitted to Phys. Lett. B

Published
1998
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14. Study of the decay D0→K−K+π−π+

Author

Daniel Ashery, L. M. Cremaldi, E. Wolin, H. A. Rubin, M. V. Purohit, A.K.S. Santha, M. Sheaff, A.B. d'Oliveira, K. O'Shaughnessy, E.M. Aitala, A. J. Slaughter, J. R. T. de Mello Neto, N. K. Copty, I. Bediaga, P.A. Kasper, A. Napier, S. MayTal-Beck, C. James, K. C. Peng, N. W. Reay, J. Leslie, K. Denisenko, D. Yi, C. Zhang, D. J. Summers, K. Gounder, A.M. Halling, L.P. Perera, Kevin Stenson, R. Weiss-Babai, D. C. Langs, J. M. De Miranda, S. Yoshida, B. Quinn, B. T. Meadows, J. A. Appel, J. Solano, R. A. Sidwell, M. D. Sokoloff, S. B. Bracker, P. R. Burchat, G. F. Fox, H.S. Carvalho, N. Witchey, R. H. Milburn, A. Fernandez, R. Zaliznyak, A. C. dos Reis, A.J. Schwartz, B. Lundberg, Simon Kwan, J.J. Reidy, T. Carter, S. Watanabe, P. Gagnon, J. Wiener, A. K. Tripathi, C. Göbel, Sudeshna Banerjee, C. L. Darling, G. Herrera, S. Amato, S. Radeztsky, S. Takach, Alberto Santoro, R. A. Burnstein, A. Rafatian, G. Hurvits, D. A. Sanders, K. Thorne, A. Nguyen, N. R. Stanton, J. C. Anjos, and G. Blaylock

Subjects
Physics, Nuclear and High Energy Physics, Amplitude, Branching fraction, Analytical chemistry, Fermilab, Measure (mathematics)
Abstract

Using data from Fermilab fixed-target experiment E791, we measure the branching ratio for D 0 → K − K + π − π + and its resonant components. We find Γ(D 0 →K − K + π − π + ) Γ(D 0 →K − π + π − π + ) =(3.13±0.37±0.36) %. A coherent amplitude analysis is used to estimate the resonant components. We measure the ratios Γ(D 0 →f) Γ(D 0 →K − π + π − π + ) to be (2.0±0.9±0.8)% for f = φρ 0 , (0.9±0.4±0.5)% for f = φπ + π − , f=K ∗0 (892) K ∗0 (892) , and f= K ∗0 (892)K + π − or K ∗0 (892)K − π + .

Published
1998
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15. Measurement of the Form-Factor Ratios forD+→K¯*0e+νe

Author

N. R. Stanton, N. K. Copty, C. Zhang, P.A. Kasper, D. Mihalcea, Kevin Stenson, A. K. Tripathi, A. C. dos Reis, S. MayTal-Beck, J. Solano, A. J. Slaughter, R. H. Milburn, B. T. Meadows, M. D. Sokoloff, G. P. Gagnon, J. R. T. de Mello Neto, P. R. Burchat, Daniel Ashery, J. Wiener, A. Napier, K. Denisenko, N. W. Reay, J. Leslie, S. Yoshida, K. C. Peng, B. Quinn, D. Yi, D. C. Langs, I. Bediaga, H. A. Rubin, R. Weiss-Babai, D. J. Summers, C. James, K. Gounder, N. Witchey, Simon Kwan, M. V. Purohit, J. M. De Miranda, J.J. Reidy, K. O'Shaughnessy, A.K.S. Santha, S. Banerjee, H.S. Carvalho, Alberto Santoro, J. C. Anjos, A. Álvarez Fernández, B. Lundberg, R. A. Burnstein, L. M. Cremaldi, M. Sheaff, J. A. Appel, E. Wolin, D. A. Sanders, G. Blaylock, A. Rafatian, G. Hurvits, T. Carter, C. L. Darling, R. A. Sidwell, L. Perera, A. J. Schwartz, S. B. Bracker, A.B. d'Oliveira, E.M. Aitala, K. Thorne, S. Takach, S. Radeztsky, A. Nguyen, G. Herrera, S. Amato, A.M. Halling, G. F. Fox, S. Watanabe, and R. Zaliznyak

Subjects
Physics, Particle physics, General Physics and Astronomy, Electron neutrino
Abstract

We present a measurement of the form-factor ratios r_V=V(0)/A_1(0) and r_2=A_2(0)/A_1(0) for the decay D^+ -> \overline K^{*0} e^+ \nu_e. The measurement is based on a signal of approximately 3000 $D^+ -> \overline K^{*0} e^+ \nu_e, \overline K^{*0} -> K^-\pi^+$ decays reconstructed in data from charm hadroproduction experiment E791 at Fermilab. The results are r_V = 1.84 +- 0.11 +- 0.08 and r_2 = 0.71 +- 0.08 +- 0.09.

Published
1998
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16. Search forD0−D0mixing and doubly-Cabibbo-suppressed decays of theD0in hadronic final states

Author

A. Nguyen, L.P. Perera, B. Lundberg, Simon Kwan, P. Gagnon, D. C. Langs, A. Napier, D. Yi, R. Weiss-Babai, Daniel Ashery, C. L. Darling, Milind Purohit, I. Bediaga, C. Zhang, M. Sheaff, A.M. Halling, A.K.S. Santha, A.B. d'Oliveira, E.M. Aitala, Alberto Santoro, H. A. Rubin, N. W. Reay, J. Leslie, K. C. Peng, N. Witchey, N. K. Copty, S. Takach, T. Carter, S. Yoshida, R. Zaliznyak, R. H. Milburn, K. O'Shaughnessy, B. T. Meadows, A. J. Schwartz, K. Thorne, J. A. Appel, A. Álvarez Fernández, M. D. Sokoloff, P. R. Burchat, P.A. Kasper, D. J. Summers, J. C. Anjos, G. Herrera, K. Gounder, J. M. De Miranda, S. B. Bracker, L. M. Cremaldi, E. Wolin, R. A. Sidwell, S. Watanabe, H.S. Carvalho, B. Quinn, R. A. Burnstein, Sudeshna Banerjee, C. James, A. J. Slaughter, A. Rafatian, S. Radeztsky, G. Hurvits, S. Amato, J. R. T. de Mello Neto, Kevin Stenson, A. C. dos Reis, J. Wiener, C. Göbel, J.J. Reidy, S. MayTal-Beck, N. R. Stanton, G. Blaylock, and A. K. Tripathi

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Pion, Hadron, Charge (physics), Sensitivity (control systems), Mixing (physics)
Abstract

We present results of a search for ${D}^{0}\ensuremath{-}{D}^{0}$ mixing and doubly-Cabibbo-suppressed decays of the ${D}^{0}$ in Fermilab experiment E791, a fixed-target charm hadroproduction experiment. We look for evidence of mixing in the decay chain ${D}^{*}\ensuremath{\rightarrow}\ensuremath{\pi}\stackrel{\ensuremath{\rightarrow}}{D}\ensuremath{\pi}(K\ensuremath{\pi}$ or $K\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\pi})$. If the charge of the pion from the ${D}^{*}$ decay is the same as the charge of the kaon from the $D$ decay (a ``wrong-sign'' event), mixing may have occurred. Mixing can be distinguished from other sources of wrong-sign events (such as doubly-Cabibbo-suppressed decays) by analyzing the distribution of decay times. We see no evidence of mixing. Allowing for $\mathrm{CP}$ violation in the interference between DCS and mixing amplitudes our fitted ratio for mixed to unmixed decay rates is ${r}_{\mathrm{mix}}{=(0.39}_{\ensuremath{-}0.32}^{+0.36}\ifmmode\pm\else\textpm\fi{}0.16)%$. This corresponds to a 90% C.L. upper limit of ${r}_{\mathrm{mix}}l0.85%$. The sensitivity of this result is comparable to that of previous measurements, but the assumptions made in fitting the data are notably more general. We present results from many fits to our data under various assumptions. If we assume ${r}_{\mathrm{mix}}=0$, we find a two-sigma wrong-sign enhancement in the $K\ensuremath{\pi}$ mode which we ascribe to doubly Cabibbo-suppressed decays. The ratios of doubly Cabibbo-suppressed decays to Cabibbo-favored decays are ${r}_{\mathrm{dcs}}(K\ensuremath{\pi}{)=(0.68}_{\ensuremath{-}0.33}^{+0.34}\ifmmode\pm\else\textpm\fi{}0.07)%$ and ${r}_{\mathrm{dcs}}(K\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\pi}{)=(0.25}_{\ensuremath{-}0.34}^{+0.36}\ifmmode\pm\else\textpm\fi{}0.03)%$.

Published
1998
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17. Asymmetries between the production of D− and D+ mesons from 500 GeV/c π− nucleon interaction as functions of x and p2

Author

D. C. Langs, A. Nguyen, J. R. T. de Mello Neto, S. Takach, B. T. Meadows, M. D. Sokoloff, P. R. Burchat, K. C. Peng, I. Bediaga, R. Zaliznyak, S. MayTal-Beck, Simon Kwan, G. Blaylock, N. Witchey, K. O'Shaughnessy, A. Fernandez, L. M. Cremaldi, E. Wolin, N. R. Stanton, S. Radeztsky, S. Yoshida, J. Wiener, R. H. Milburn, E.M. Aitala, P. Gagnon, A. Napier, K. Denisenko, Sudeshna Banerjee, S. B. Bracker, C. Göbel, C. Zhang, D. J. Summers, D. Yi, M. V. Purohit, K. Gounder, J. A. Appel, J. M. De Miranda, J.J. Reidy, N. K. Copty, R. Weiss-Babai, A.J. Schwartz, S. Amato, L.P. Perera, A.K.S. Santha, B. Lundberg, N. W. Reay, J. Leslie, C. L. Darling, A.B. d'Oliveira, A.M. Halling, Kevin Stenson, B. Quinn, Daniel Ashery, K. Thorne, S. Watanabe, A. J. Slaughter, H. A. Rubin, D. Mihalcea, C. James, A. C. dos Reis, R. A. Sidwell, Alberto Santoro, A. K. Tripathi, R. A. Burnstein, A. Rafatian, G. Hurvits, M. Sheaff, H.S. Carvalho, G. Herrera, J. C. Anjos, P.A. Kasper, and T. Carter

Subjects
Physics, Nuclear and High Energy Physics, Meson, High Energy Physics::Lattice, media_common.quotation_subject, Nuclear Theory, High Energy Physics::Phenomenology, Asymmetry, Charm quark, Nuclear physics, High Energy Physics::Experiment, Fermilab, Nuclear Experiment, Nucleon, media_common
Abstract

We present measurements of the production of Ds− mesons relative to Ds+ mesons as functions of xF and of pt2 for a sample of 2445 Ds decays to φπ. The Ds mesons were produced in Fermilab experiment E791 with 500 GeV/c π− mesons incident on one platinum and four carbon foil targets. The acceptance-corrected integrated asymmetry in the xF range −0.1 to 0.5 for Ds± mesons is 0.032 ± 0.022 ± 0.022, consistent with no net asymmetry. We compare the results as functions of xF and pt2 to predictions and to the large production asymmetry observed for D± mesons in the same experiment. These comparisons support the hypothesis that production asymmetries come from the fragmentation process and not from the charm quark production itself.

Published
1997
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18. The doubly Cabibbo-suppressed decay D+ → K+ π− π+

Author

S. Yoshida, N. Witchey, A. Fernandez, L. M. Cremaldi, E. Wolin, B. Quinn, L.P. Perera, P.A. Kasper, D. C. Langs, S. B. Bracker, S. Takach, Alberto Santoro, K. O'Shaughnessy, N. K. Copty, R. A. Sidwell, Kevin Stenson, A. Nguyen, S. May Tal-Beck, R. A. Burnstein, A. Napier, D. J. Summers, K. Gounder, K. Denisenko, J. A. Appel, S. Watanabe, J. M. De Miranda, A. Rafatian, J.J. Reidy, K. C. Peng, D. Yi, A.J. Schwartz, M. V. Purohit, R. H. Milburn, R. Weiss-Babai, B. Lundberg, G. Hurvits, I. Bediaga, A.M. Halling, S. Radeztsky, A. C. dos Reis, A.K.S. Santha, K. Thorne, Daniel Ashery, N. R. Stanton, T. Carter, Simon Kwan, A.B. d'Oliveira, C. L. Darling, E.M. Aitala, Sudeshna Banerjee, H. A. Rubin, G. Herrera, P. Gagnon, A. J. Slaughter, B. T. Meadows, N. W. Reay, J. Leslie, M. D. Sokoloff, P. R. Burchat, S. Amato, J. R. T. de Mello Neto, G. Blaylock, R. Zaliznyak, H.S. Carvalho, J. C. Anjos, J. Wiener, C. James, C. Zhang, A. K. Tripathi, and M. Sheaff

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Branching fraction, Analytical chemistry, Dalitz plot, Fermilab
Abstract

We report the observation of the doubly Cabibbo-suppressed decay D + → K + π − π + in data from Fermilab charm hadroproduction experiment E791. With a signal of 59 ± 13 events we measured the ratio of the branching fraction for this mode to that of the Cabibbo-favored decay D + → K − π + π + to be B (D + → K + π − π + ) / B ( D + → K − π + π + ) = (7.7 ± 1.7 ± 0.8) × 10 −3 . A Dalitz plot analysis was performed to search for resonant structures.

Published
1997
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19. Observation of D - π production correlations in 500 GeV π− - N interactions

Author

E.M. Aitala, S. Amato, J.C. Anjos, J.A. Appel, D. Ashery, S. Banerjee, I. Bediaga, G. Blaylock, S.B. Bracker, P.R. Burchat, R.A. Burnstein, T. Carter, H.S. Carvalho, N.K. Copty, I. Costa, L.M. Cremaldi, C. Darling, K. Denisenko, A. Fernandez, P. Gagnon, S. Gerzon, K. Gounder, A.M. Halling, G. Herrera, G. Hurvits, C. James, P.A. Kasper, S. Kwan, D.C. Langs, J. Leslie, B. Lundberg, S. MayTal-Beck, B.T. Meadows, J.R.T. de Mello Neto, R.H. Milburn, J.M. de Miranda, A. Napier, A. Nguyen, A.B. d'Oliveira, K. O'Shaughnessy, K.C. Peng, L.P. Perera, M.V. Purohit, B. Quinn, S. Radeztsky, A. Rafatian, N.W. Reay, J.J. Reidy, A.C. dos Reis, H.A. Rubin, A.K.S. Santha, A.F.S. Santoro, A.J. Schwartz, M. Sheaff, R.A. Sidwell, A.J. Slaughter, M.D. Sokoloff, N.R. Stanton, K. Stenson, D.J. Summers, S. Takach, K. Thorne, A.K. Tripathi, S. Watanabe, R. Weiss-Babai, J. Wiener, N. Witchey, E. Wolin, D. Yi, S. Yoshida, R. Zaliznyak, and C. Zhang

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, FOS: Physical sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), symbols.namesake, Pion, Fragmentation (mass spectrometry), Phase space, Pi, symbols, Feynman diagram, High Energy Physics::Experiment, Fermilab, Nuclear Experiment
Abstract

We study the charge correlations between charm mesons produced in 500 GeV pi- - N interactions and the charged pions produced closest to them in phase space. With 110,000 fully reconstructed D mesons from experiment E791 at Fermilab, the correlations are studied as functions of the Dpi - D mass difference and of Feynman x. We observe significant correlations which appear to originate from a combination of sources including fragmentation dynamics, resonant decays, and charge of the beam., Comment: 12 pages and 2 figures

Published
1997
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20. Measurement of the branching ratio

Author

E.M. Aitala, S. Amato, J.C. Anjos, J.A. Appel, D. Ashery, S. Banerjee, I. Bediaga, G. Blaylock, S.B. Bracker, P.R. Burchat, R.A. Burnstein, T. Carter, H.S. Carvalho, N.K. Copty, L.M. Cremaldi, C. Darling, K. Denisenko, A. Fernandez, P. Gagnon, K. Gounder, A.M. Halling, G. Herrera, G. Hurvits, C. James, P.A. Kasper, S. Kwan, D.C. Langs, J. Leslie, B. Lundberg, S. MayTal-Beck, B. Meadows, J.R.T. de Mello Neto, R.H. Milburn, J.M. de Miranda, A. Napier, A. Nguyen, A.B. d'Oliveira, K. O'Shaughnessy, K.C. Peng, L.P. Perera, M.V. Purohit, B. Quinn, S. Radeztsky, A. Rafatian, N.W. Reay, J.J. Reidy, A.C. dos Reis, H.A. Rubin, A.K.S. Santha, A.F.S. Santoro, A.J. Schwartz, M. Sheaff, R.A. Sidwell, A.J. Slaughter, M.D. Sokoloff, N.R. Stanton, K. Stenson, D.J. Summers, S. Takach, K. Thorne, A.K. Tripathi, S. Watanabe, R. Weiss-Babai, J. Wiener, N. Witchey, E. Wolin, D. Yi, S. Yoshida, R. Zaliznyak, and C. Zhang

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Branching fraction, Charm (quantum number)
Abstract

We report a measurement of the branching ratio B(D+-->rho^0 l nu)/ B(D+-->K*0 l nu) from the Fermilab charm hadroproduction experiment E791. Based on signals of 49+-17 events in the D+--> rho^0 e nu mode and 54+-18 events in the D+--> rho^0 mu nu mode, we measure B(D+-->rho^0 e nu)/B(D+-->K*0 e nu) = 0.045+-0.014+-0.009, and B(D+-->rho^0 mu nu)/B(D+-->K*0 mu nu) = 0.051+-0.015+-0.009. Combining the results from both the electronic and muonic modes, we obtain B(D+-->rho^0 l nu)/B(D+-->K*0 l nu) = 0.047+-0.013. This result is compared to theoretical predictions.

Published
1997
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21. Mass splitting and production of Σc0 and Σc++ measured in 500 GeV π− -N interactions

Author

M. Sheaff, Michael Sokoloff, I. Costa, K. O'Shaughnessy, S. Gerzon, Milind Purohit, I. Bediaga, A. Rafatian, H.S. Carvalho, Don Summers, J. G. Smith, L. M. Cremaldi, E. Wolin, R.A. Burnstein, B. Quinn, A. Nguyen, S. Takach, E.M. Aitala, P.A. Kasper, Sudeshna Banerjee, J.J. Reidy, H. A. Rubin, Aleardo Manacero, G. Hurvits, N. R. Stanton, D. C. Langs, C. L. Darling, S. Amato, K. Gounder, J. M. De Miranda, S. B. Bracker, K. C. Peng, J. R. T. de Mello Neto, J. Wiener, J. Lichtenstadt, C. James, Simon Kwan, B. Lundberg, A.J. Slaughter, R. H. Milburn, S. MayTal-Beck, N. Kondakis, N. Witchey, A. K. Tripathi, A.K.S. Santha, T. Carter, K. Sugano, A. Fernandez, Jürgen Engelfried, Patricia R. Burchat, A.J. Schwartz, P. Gagnon, D. Ashery, G. Blaylock, S. Radeztsky, S. Watanabe, L.P. Perera, J. A. Appel, J. C. Anjos, Alberto Santoro, N. W. Reay, J. Leslie, A.M. Halling, Brian Meadows, R. Zaliznyak, R. A. Sidwell, K. Thorne, G. Herrera, A. Napier, K. Denisenko, D. Yi, R. Weiss-Babai, A. C. dos Reis, A. B. d'Oliveira, C. Zhang, and N. K. Copty

Subjects
Physics, Nuclear and High Energy Physics, Mass spectrum, Analytical chemistry, Spectral line
Abstract

From a sample of 2722 ± 78 Λc+ decaying to the pK−π+ final state, we have observed, in the hadroproduction experiment E791 at Fermilab, 143 ± 20 Σc0 and 122 ± 18 Σc++ through their decays to Λc+π±. The mass difference M(Σc0) − M(Λc+) is measured to be (167.38 ± 0.29 ± 0.15) MeV; for M(Σc++) − M(Λc+), we find (167.76 ± 0.29 ± 0.15) MeV. The rate of Λc+ production from decays of the Σc triplet is (22 ± 2 ± 3) % of the total Λc+ production assuming equal rate of production from all three, as measured for Σc0 and Σc++. We do not observe a statistically significant Σc baryon-antibaryon production asymmetry. The xF and pt2 spectra of Λc+ from Σc decays are observed to be similar to those for all Λc+'s produced.

Published
1996
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22. Asymmetries between the production of D+ and D− mesons from 500 GeV/c π−-nucleus interactions as a function of xF and pt2

Author

S. Gerzon, A. Álvarez Fernández, N. Witchey, A. Nguyen, T. Carter, J. G. Smith, B. T. Meadows, B. Quinn, L. M. Cremaldi, E. Wolin, M. D. Sokoloff, N. R. Stanton, P. R. Burchat, D. C. Langs, R. A. Burnstein, A. Napier, A. Rafatian, M. V. Purohit, K. Denisenko, D. Yi, C. Zhang, Daniel Ashery, R. Weiss-Babai, A.K.S. Santha, G. Hurvits, J.J. Reidy, B. Lundberg, K. O'Shaughnessy, A.B. d'Oliveira, E.M. Aitala, K. Sugano, P.A. Kasper, S. Amato, K. C. Peng, Alberto Santoro, H. A. Rubin, S. Banerjee, A. J. Slaughter, S. MayTal-Beck, D. Granite, N. Kondakis, I. Bediaga, L. Perera, J. Wiener, P. Gagnon, J. R. T. de Mello Neto, G. Blaylock, C. Göbel, R. A. Sidwell, K. Thorne, S. Watanabe, J. Astorga, C. L. Darling, C. James, D. J. Summers, K. Gounder, J. M. De Miranda, R. H. Milburn, R. Zaliznyak, H.S. Carvalho, A. C. Reis, A.M. Halling, S. Takach, S. Radeztsky, A. J. Schwartz, G. Herrera, Aleardo Manacero, J. A. Appel, Simon Kwan, N. W. Reay, J. Leslie, S. B. Bracker, M. Aryal, J. C. Anjos, A. K. Tripathi, M. Sheaff, I. Costa, and J. Lichtenstadt

Subjects
Physics, Quark, Nuclear and High Energy Physics, Particle physics, Meson, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, FOS: Physical sciences, Function (mathematics), High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Pi, High Energy Physics::Experiment, Production (computer science), Fermilab, Nuclear Experiment, Nucleon, Beam (structure)
Abstract

We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used.

Published
1996
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23. Publisher’s Note: Model-independent measurement ofS-waveK−π+systems usingD+→Kππdecays from Fermilab E791 [Phys. Rev. D 73, 032004 (2006)]

Author

P. Gagnon, R. Zaliznyak, A.M. Halling, G. Blaylock, M. V. Purohit, S. Banerjee, N. W. Reay, C. L. Darling, J. Leslie, B. T. Meadows, A.B. d'Oliveira, E.M. Aitala, D. C. Langs, M. D. Sokoloff, A.K.S. Santha, P. R. Burchat, N. R. Stanton, B. Lundberg, G. F. Fox, D. J. Summers, Simon Kwan, D. Mihalcea, K. Gounder, K. C. Peng, J. M. De Miranda, S. Devmal, K. O'Shaughnessy, S. Watanabe, M. Sheaff, P.A. Kasper, A. C. dos Reis, N. Witchey, S. M. Yang, A. Napier, K. Denisenko, C. Zhang, S. Yoshida, J. Wiener, C. Göbel, A. Álvarez Fernández, D. Yi, S. B. Bracker, Alberto Santoro, W. M. Dunwoodie, R. H. Milburn, A. J. Slaughter, D. A. Sanders, R. Weiss-Babai, S. Amato, L. M. Cremaldi, R. A. Burnstein, I. Bediaga, E. Wolin, L. Perera, J.J. Reidy, B. Quinn, J. A. Appel, A. Rafatian, K. Thorne, A. Nguyen, S. Takach, A. Massafferri, G. Hurvits, R. A. Sidwell, S. Radeztsky, S. MayTal-Beck, T. Carter, A. K. Tripathi, C. James, J. Magnin, Kevin Stenson, J. C. Anjos, J. R. T. de Mello Neto, A. J. Schwartz, G. Herrera, H.S. Carvalho, N. K. Copty, J. Solano, Daniel Ashery, H. A. Rubin, and R. J. Stefanski

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Particle decay, S-wave, Pi, Fermilab
Published
2006
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24. Effects of transverse coupling on transverse beam size, simulation and measurements

Author

A.M. Halling

Subjects
Physics, Aperture, Equations of motion, Particle accelerator, Computational physics, law.invention, Transverse plane, law, Physics::Accelerator Physics, Thermal emittance, Fermilab, Beam emittance, Atomic physics, Magnetosphere particle motion
Abstract

The equations of motion for particles in an accelerator lattice show that a larger physical aperture is required to hold a beam of constant invariant emittance if there is transverse coupling of the tunes. The results of a tracking simulation of particle motion in the Fermilab accumulator ring are discussed, and results are shown from beam tests carried out in the accumulator to demonstrate this effect. >

Published
2002
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25. The design and performance of a high sensitivity loss monitor system for use in the Fermilab antiproton rings

Author

A. Hahn, A.M. Halling, and J.R. Zagel

Subjects
Physics, Physics::Instrumentation and Detectors, Nuclear engineering, Particle accelerator, Scintillator, law.invention, Nuclear physics, law, Antiproton, Scintillation counter, Measuring instrument, Fermilab, Sensitivity (electronics), Beam (structure)
Abstract

As part of a general laboratory cleanup of hazardous materials from the accelerator enclosures we have replaced the liquid scintillator based paint can type beam loss monitors with improved loss monitors based an plastic scintillator. This paper describes the design of these counters and their performance in the PBAR source. >

Published
2002
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26. Dalitz Plot Analysis of the DecayD+→K−π+π+and Indication of a Low-Mass ScalarKπResonance

Author

dos Reis Ac, S. M. Yang, J. Magnin, S. Yoshida, K. C. Peng, A. K. Tripathi, S. MayTal-Beck, P.A. Kasper, A.M. Halling, D. A. Sanders, J. C. Anjos, Simon Kwan, K. O'Shaughnessy, L. Perera, S. Takach, H.S. Carvalho, C. James, Alberto Santoro, K. Thorne, A. Álvarez Fernández, N. Witchey, J. Wiener, B. Lundberg, A. J. Slaughter, S. Banerjee, C. Göbel, D. C. Langs, L. M. Cremaldi, E. Wolin, C. Zhang, J.J. Reidy, A. J. Schwartz, D. Mihalcea, S. Radeztsky, R. A. Sidwell, B. Quinn, A. Nguyen, N. W. Reay, J. Leslie, I. Bediaga, A. Napier, G. Herrera, R. Zaliznyak, K. Denisenko, R. H. Milburn, G. Blaylock, M. V. Purohit, de Mello Neto, M. Sheaff, P. Gagnon, J. A. Appel, S. Amato, D. J. Summers, K. Gounder, A.K.S. Santha, N. R. Stanton, D. Yi, T. Carter, R. Weiss-Babai, Solano Salinas Cj, G. F. Fox, C. L. Darling, A. Massafferri, de Miranda Jm, B. T. Meadows, Kevin Stenson, P. R. Burchat, S. Watanabe, R. A. Burnstein, A. Rafatian, A.B. d'Oliveira, E.M. Aitala, G. Hurvits, S. B. Bracker, R. J. Stefanski, N. K. Copty, Sokoloff, Daniel Ashery, H. A. Rubin, and S. Devmal

Subjects
Physics, Particle decay, Particle physics, Pion, Meson, Hadron, General Physics and Astronomy, Resonance, Dalitz plot, Elementary particle, Boson
Abstract

We study the Dalitz plot of the decay ${D}^{+}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}$ with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known $K\ensuremath{\pi}$ resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the ${K}_{0}^{*}(1430)$ to float, we obtain values consistent with those from PDG but the ${\ensuremath{\chi}}^{2}$ per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass $797\ifmmode\pm\else\textpm\fi{}19\ifmmode\pm\else\textpm\fi{}43\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{\mathrm{c}}^{\mathrm{2}}$ and width $410\ifmmode\pm\else\textpm\fi{}43\ifmmode\pm\else\textpm\fi{}87\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{\mathrm{c}}^{2}$. The mass and width of the ${K}_{0}^{*}(1430)$ become $1459\ifmmode\pm\else\textpm\fi{}7\ifmmode\pm\else\textpm\fi{}5\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{\mathrm{c}}^{\mathrm{2}}$ and $175\ifmmode\pm\else\textpm\fi{}12\ifmmode\pm\else\textpm\fi{}12\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{\mathrm{c}}^{\mathrm{2}}$, respectively. Our results provide new information on the scalar sector in hadron spectroscopy.

Published
2002
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27. Differential cross sections, charge production asymmetry, and spin-density matrix elements for D*(2010) produced in 500 GeV/c pi^- nucleon interactions

Author

J.J. Reidy, A. J. Slaughter, R. A. Burnstein, Kevin Stenson, A. Rafatian, J. A. Appel, R. Zaliznyak, D. J. Summers, K. Gounder, J. M. De Miranda, G. Hurvits, C. James, P.A. Kasper, N. R. Stanton, A. Massafferri, A. Nguyen, C. Zhang, C. J. Solano Salinas, M. V. Purohit, S. MayTal-Beck, K. O'Shaughnessy, B. T. Meadows, J. R. T. de Mello Neto, M. D. Sokoloff, P. R. Burchat, A.M. Halling, S. M. Yang, N. Witchey, A.K.S. Santha, H.S. Carvalho, N. W. Reay, J. Leslie, A.K. Tripathi, S. Yoshida, A. Fernandez, J. Magnin, Alberto Santoro, S. Takach, D. C. Langs, J. C. Anjos, T. Carter, S. B. Bracker, Simon Kwan, G. F. Fox, G. Blaylock, K. C. Peng, R. H. Milburn, P. Gagnon, R. A. Sidwell, S. Radeztsky, M. Sheaff, B. Quinn, S. Watanabe, B. Lundberg, Sudeshna Banerjee, C. L. Darling, A. J. Schwartz, I. Bediaga, D. Mihalcea, S. Amato, A. C. dos Reis, L. M. Cremaldi, E. Wolin, A.B. d'Oliveira, E.M. Aitala, D. A. Sanders, G. Herrera, K. Thorne, S. Devmal, L.P. Perera, A. Napier, K. Denisenko, D. Yi, R. Weiss-Babai, J. Wiener, C. Göbel, N. K. Copty, R. J. Stefanski, Daniel Ashery, and H. A. Rubin

Subjects
Physics, Scattering cross-section, Nuclear and High Energy Physics, media_common.quotation_subject, FOS: Physical sciences, Polarization (waves), Asymmetry, High Energy Physics - Experiment, Nuclear physics, symbols.namesake, High Energy Physics - Experiment (hep-ex), Transverse momentum, symbols, Feynman diagram, High Energy Physics::Experiment, Fermilab, Atomic physics, Spin density, Nucleon, Nuclear Experiment, media_common
Abstract

We report differential cross sections for the production of D*(2010) produced in 500 GeV/c pi^- nucleon interactions from experiment E791 at Fermilab, as functions of Feynman-x (x_F) and transverse momentum squared (p_T^2). We also report the D* +/- charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are \eta= 0.01 +- 0.02 and -0.01 +- 0.02 for leading and non-leading particles, respectively., Comment: LaTeX2e (elsart.cls). 13 pages, 6 figures (eps files). Submitted to Physics Letters B

Published
2002

28. Improvements to the ease of LINAC Dataset generation for high energy

Author

S.F. Nitodas, J. Murphy, and A.M. Halling

Subjects
Physics, Ion beam, business.industry, Electrical engineering, Phase (waves), Linear particle accelerator, Resonator, Acceleration, Quality (physics), Ion implantation, Electronic engineering, Physics::Accelerator Physics, business, Beam (structure)
Abstract

High-energy ion implanters using RF acceleration have advantages over electrostatic implementations. However, in order to generate quality beams each successive RF resonator phase and amplitude must be adjusted to accept beam from the preceding resonator and accelerate it in a manner that produces the desired acceleration. A new method of obtaining optimal beam tuning is described. Test results are shown documenting that optimum beam performance can be achieved with minimal tuning times.

Published
2002
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29. Direct measurement of the pion valence-quark momentum distribution, the pion light-cone wave function squared

Author

A. Napier, K. Denisenko, D. Yi, R. Weiss-Babai, R. A. Burnstein, J. Wiener, A. Rafatian, L.P. Perera, A. J. Schwartz, B. Lundberg, A.M. Halling, C. Göbel, N. R. Stanton, G. Hurvits, N. W. Reay, A. J. Slaughter, J. Leslie, S. Radeztsky, A. Nguyen, G. Herrera, Alberto Santoro, S. Gerzon, J. A. Appel, R. A. Sidwell, B. T. Meadows, A. Álvarez Fernández, Kevin Stenson, L. M. Cremaldi, E. Wolin, D. J. Summers, K. Gounder, J. M. De Miranda, Daniel Ashery, H. A. Rubin, Simon Kwan, N. Witchey, D.C. Langs, M. V. Purohit, P. Gagnon, D. A. Sanders, R. H. Milburn, Sudeshna Banerjee, P.A. Kasper, A.K.S. Santha, N. K. Copty, K. Thorne, K. C. Peng, S. Takach, S. Amato, J. C. Anjos, I. Bediaga, M. Sheaff, G. F. Fox, G. Blaylock, R. Zaliznyak, A.B. d'Oliveira, E.M. Aitala, C. L. Darling, S. Watanabe, J. R. T. de Mello Neto, D. Mihalcea, H.S. Carvalho, A. C. dos Reis, S. Deval, Michael Sokoloff, J. Lichtenstadt, K. O'Shaughnessy, S. M. Yang, S. Yoshida, B. Quinn, S. MayTal-Beck, A.K. Tripathi, S. B. Bracker, J. Solano, J.J. Reidy, Patricia R. Burchat, T. Carter, R. J. Stefanski, C. Zhang, and C. James

Subjects
Quark, Physics, Particle physics, Valence (chemistry), General Physics and Astronomy, FOS: Physical sciences, Square (algebra), High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, Light cone, Transverse momentum, High Energy Physics::Experiment, Fermilab, Wave function, Nuclear Experiment
Abstract

We present the first direct measurements of the pion valence quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV/c $��^-$ into di-jets from a platinum target at Fermilab experiment E791. The results show that the $|q\bar {q}>$ light-cone asymptotic wave function, which was developed using perturbative QCD methods, describes the data well for $Q^2 \sim 10 ~{\rm (GeV/c)^2}$ or more. We also measured the transverse momentum distribution of the diffractive di-jets., 13 pages, 4 figures

Published
2000

30. Observation of color-transparency in diffractive dissociation of pions

Author

R. H. Milburn, C. Zhang, S. B. Bracker, A. Nguyen, P. Gagnon, C. L. Darling, D. J. Summers, B. Lundberg, K. Gounder, J. M. De Miranda, R. A. Burnstein, Kevin Stenson, A. Álvarez Fernández, A. Napier, K. Denisenko, A. Rafatian, G. Blaylock, L. M. Cremaldi, E. Wolin, M. V. Purohit, B. Quinn, D. Yi, D. C. Langs, R. Weiss-Babai, S. Gerzon, A.K.S. Santha, J. Wiener, S. M. Yang, G. Hurvits, A. J. Schwartz, P.A. Kasper, J.J. Reidy, R. J. Stefanski, S. Yoshida, M. Sheaff, C. James, C. Göbel, K. O'Shaughnessy, Daniel Ashery, A. J. Slaughter, J. R. T. de Mello Neto, D. A. Sanders, B. T. Meadows, S. Radeztsky, Alberto Santoro, L. Perera, M. D. Sokoloff, H. A. Rubin, K. C. Peng, N. K. Copty, G. Herrera, K. Thorne, S. Banerjee, T. Carter, J. C. Anjos, R. Zaliznyak, J. Solano, N. Witchey, N. R. Stanton, S. MayTal-Beck, H.S. Carvalho, I. Bediaga, A.B. d'Oliveira, E.M. Aitala, S. Devmal, R. A. Sidwell, Patricia R. Burchat, S. Amato, G. F. Fox, A. K. Tripathi, S. Watanabe, A.M. Halling, S. Takach, N. W. Reay, J. Leslie, Simon Kwan, J. A. Appel, D. Mihalcea, A. C. dos Reis, and J. Lichtenstadt

Subjects
Physics, Particle physics, Scattering, General Physics and Astronomy, Sigma, chemistry.chemical_element, Parameterized complexity, FOS: Physical sciences, Dissociation (chemistry), High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, chemistry, Transverse momentum, Color transparency, High Energy Physics::Experiment, Platinum, Nuclear Experiment
Abstract

We have studied the diffractive dissociation into di-jets of 500 GeV/c pions scattering coherently from carbon and platinum targets. Extrapolating to asymptotically high energies (where t_{min} approaches 0) we find that when the per-nucleus cross-section for this process is parameterized as $\sigma = \sigma_0 A^{\alpha}, \alpha$ has values near 1.6, the exact result depending on jet transverse momentum. These values are in agreement with those predicted by theoretical calculations of color-transparency., Comment: 9 pages, 3 figures

Published
2000
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31. Measurements of Lifetimes and a Limit on the Lifetime Difference in the Neutral D-Meson System

Author

A. J. Schwartz, Kevin Stenson, N. K. Copty, D. J. Summers, K. Gounder, J. M. De Miranda, S. M. Yang, G. Blaylock, G. Herrera, J. R. T. de Mello Neto, A.M. Halling, N. Witchey, S. Yoshida, J. Solano, A.B. d'Oliveira, E.M. Aitala, T. Carter, G. F. Fox, A. Napier, K. Denisenko, S. Banerjee, H.S. Carvalho, D. Yi, R. Zaliznyak, K. O'Shaughnessy, Alberto Santoro, P.A. Kasper, R. Weiss-Babai, S. Watanabe, R. H. Milburn, S. Takach, Daniel Ashery, A. J. Slaughter, H. A. Rubin, A. Álvarez Fernández, P. Gagnon, B. Quinn, D. C. Langs, S. B. Bracker, N. W. Reay, J. Leslie, S. Amato, B. T. Meadows, L. M. Cremaldi, E. Wolin, M. D. Sokoloff, A. Nguyen, C. L. Darling, M. V. Purohit, J. Wiener, J. A. Appel, A.K.S. Santha, C. Göbel, R. J. Stefanski, J. C. Anjos, I. Bediaga, R. A. Burnstein, B. Lundberg, N. R. Stanton, Simon Kwan, A. Rafatian, D. A. Sanders, L. Perera, M. Sheaff, G. Hurvits, K. Thorne, S. Radeztsky, R. A. Sidwell, Patricia R. Burchat, A. K. Tripathi, K. C. Peng, C. James, C. Zhang, D. Mihalcea, A. C. dos Reis, S. MayTal-Beck, and J.J. Reidy

Subjects
Physics, Particle decay, Crystallography, Particle physics, High Energy Physics - Experiment (hep-ex), Meson, D meson, General Physics and Astronomy, FOS: Physical sciences, State (functional analysis), High Energy Physics - Experiment
Abstract

Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we report the first directly measured constraint on the decay-width difference Delta Gamma for the mass eigenstates of the D0-D0bar system. We obtain our result from lifetime measurements of the decays D0 --> K-pi+ and D0 --> K-K+, under the assumption of CP invariance, which implies that the CP eigenstates and the mass eigenstates are the same. The lifetime of D0 --> K-K+ (the CP-even final state is ��_KK = 0.410 +/- 0.011 +/- 0.006 ps, and the lifetime of D0 --> K-pi+ (an equal mixture of CP-odd and CP-even final states is tau_Kpi = 0.413 +/- 0.003 +/- 0.004 ps. The decay-width difference is Delta Gamma = 2(Gamma_KK - Gamma_Kpi) = 0.04 +/- 0.14 +/- 0.05 ps^-1. We relate these measurements to measurements of mixing in the neutral D-meson system., 8 pages + 3 figures + 2 tables

Published
1999
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32. Search for Rare and Forbidden Dilepton Decays of the D+, Ds, and D0 Charmed Mesons

Author

E.M. Aitala, S. Amato, J.C. Anjos, J.A. Appel, D. Ashery, S. Banerjee, I. Bediaga, G. Blaylock, S.B. Bracker, P.R. Burchat, R.A. Burnstein, T. Carter, H.S. Carvalho, N.K. Copty, L.M. Cremaldi, C. Darling, K. Denisenko, S. Devmal, A. Fernandez, G.F. Fox, P. Gagnon, C. Gobel, K. Gounder, A.M. Halling, G. Herrera, G. Hurvits, C. James, P.A. Kasper, S. Kwan, D.C. Langs, J. Leslie, B. Lundberg, J. Magnin, S. MayTal-Beck, B. Meadows, J.R.T. de Mello Neto, D. Mihalcea, R.H. Milburn, J.M. de Miranda, A. Napier, A. Nguyen, A.B. d'Oliveira, K. O'Shaughnessy, K.C. Peng, L.P. Perera, M.V. Purohit, B. Quinn, S. Radeztsky, A. Rafatian, N.W. Reay, J.J. Reidy, A.C. dos Reis, H.A. Rubin, D.A. Sanders, A.K.S. Santha, A.F.S. Santoro, A.J. Schwartz, M. Sheaff, R.A. Sidwell, A.J. Slaughter, M.D. Sokoloff, J. Solano, N.R. Stanton, R.J. Stefanski, K. Stenson, D.J. Summers, S. Takach, K. Thorne, A.K. Tripathi, S. Watanabe, R. Weiss-Babai, J. Wiener, N. Witchey, E. Wolin, S.M. Yang, D. Yi, S. Yoshida, R. Zaliznyak, and C. Zhang

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Particle physics, Muon, Meson, Neutral current, High Energy Physics::Phenomenology, FOS: Physical sciences, Electron, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics::Experiment, Fermilab, Charm (quantum number)
Abstract

We report the results of a search for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. Using data from Fermilab charm hadroproduction experiment E791, we examine the pi,l,l and K,l,l decay modes of D+ and Ds and the l+l- decay modes of D0. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 24 decay modes examined. Eight of these modes have no previously reported limits, and fourteen are reported with significant improvements over previously published results., Comment: 12 pages, 3 figures, LaTeX, elsart.cls, epsf.sty, amsmath.sty Submitted to Physics Letters B

Published
1999
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33. Search for CP violation in charged D meson decays

Author

E.M. Aitala, S. Amato, J.C. Anjos, J.A. Appel, D. Ashery, S. Banerjee, I. Bediaga, G. Blaylock, S.B. Bracker, P.R. Burchat, R.A. Burnstein, T. Carter, H.S. Carvalho, N.K. Copty, L.M. Cremaldi, C. Darling, K. Denisenko, A. Fernandez, P. Gagnon, C. Gobel, K. Gounder, A.M. Halling, G. Herrera, G. Hurvits, C. James, P.A. Kasper, S. Kwan, D.C. Langs, J. Leslie, B. Lundberg, S. MayTal-Beck, B. Meadows, J.R.T. de Mello Neto, R.H. Milburn, J.M. de Miranda, A. Napier, A. Nguyen, A.B. d'Oliveira, K. O'Shaughnessy, K.C. Peng, L.P. Perera, M.V. Purohit, B. Quinn, S. Radeztsky, A. Rafatian, N.W. Reay, J.J. Reidy, A.C. dos Reis, H.A. Rubin, A.K.S. Santha, A.F.S. Santoro, A.J. Schwartz, M. Sheaff, R.A. Sidwell, A.J. Slaughter, M.D. Sokoloff, N.R. Stanton, K. Stenson, D.J. Summers, S. Takach, K. Thorne, A.K. Tripathi, S. Watanabe, R. Weiss-Babai, J. Wiener, N. Witchey, E. Wolin, D. Yi, S. Yoshida, R. Zaliznyak, and C. Zhang

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, FOS: Physical sciences, Asymmetry, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), D meson, Pi, CP violation, Charm (quantum number), Fermilab, media_common
Abstract

We report results of a search for CP violation in the singly Cabibbo-suppressed decays D+ -> K- K+ pi+, phi pi+, K*(892)0 K+, and pi- pi+ pi+ based on data from the charm hadroproduction experiment E791 at Fermilab. We search for a difference in the D+ and D- decay rates for each of the final states. No evidence for a difference is seen. The decay rate asymmetry parameters A(CP), defined as the difference in the D+ and D- decay rates divided by the sum of the decay rates, are measured to be: A(CP)(K K pi) = -0.014 +/- 0.029, A(CP)(phi pi) = -0.028 +/- 0.036, A(CP)(K*(892) K) = -0.010 +/- 0.050, and A(CP)(pi pi pi) = -0.017 +/- 0.042., 13 pages, 5 figures, 1 table; Elsevier LaTeX

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