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Stephen Takach

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Kansas State University

Omkar Kushwaha, Ph.D.

IIT Madras

Ειρήνη Σιδερίδου-Καραγιαννίδου

Aristotle University of Thessaloniki

University of Jordan

Applied Chemistry Research Center

Zdeno Špitalský

Slovak Academy of Sciences

O O Santana Pérez

Universitat Politecnica de Catalunya

UCLouvain (University of Louvain)

Patricia Krawczak

Institut Mines-Telecom

The Ohio State University

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Papers by Stephen Takach

Measurement of the b anti-b production cross-section in 920-GeV fixed target proton nucleus collisions

DESY-HERA. Measurement of the B-BBAR production cross section in 920 GeV pr oton nuclear collisio... more DESY-HERA. Measurement of the B-BBAR production cross section in 920 GeV pr oton nuclear collisions using carbon and titanium targets. The B-BBAR production is tagged via decays into J/PSI. Both E+ E- and MU+ MU- channels are reconstructed. The data are normalised to a prompt J/PSI production cross section of 357 +- 8 +- 27 nb/nucleon determined from previous measurements rescaled in energy and corrected for atomic number dependence The A dependence of the cross section is taken to be SIG(PA) = A^alpha SIG(PP) with alpha = 0.955 +- 0.005 for the J/PSI production and SIG(PA) = A SIG(PP) for the BBAR production.

Asymmetries in the production of Lambda(c)+ and Lambda(c)- baryons in 500-GeV/c pi- nucleon interactions

FNAL-TEV accelerator. Asymmetries in the production of Lambda/c+ and Lambda/c- baryons in 500-GeV... more

AIP Conference Proceedings, 1992

Fermilab E791, a very high statistics charm particle experiment, recently completed its data taki... more Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.

$Research paper thumbnail of Correlations between D and $${\overline D}$$ mesons produced in 500 GeV/cπ−-nucleon interactions$

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

EPJ direct, 2000

We present a study of correlations between D and D mesons produced in 500 GeV/c π −-nucleon inter... more We present a study of correlations between D and D mesons produced in 500 GeV/c π −-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 Muon Detector at the HERA-B experiment

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2001

The HERA-B experiment is designed to study beauty particle production and decay using the HERA 92... more The HERA-B experiment is designed to study beauty particle production and decay using the HERA 920 GeV proton beam interactions with an internal target. The Muon detector provides identification for muons having momenta greater than 5 GeV/c and triggering on the muon pair from J=c decay. Three different chamber types are employed for operation in a high-rate environment. The overall design, performance and current status are discussed.

Observation of D - π production correlations in 500 GeV π− - N interactions

Physics Letters B, 1997

We study the charge correlations between charm mesons produced in 500 GeV π − − N interactions an... more We study the charge correlations between charm mesons produced in 500 GeV π − − 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 Dπ − 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.

Search for the pentaquark via the decay

Physics Letters B, 1999

Measurement of the form-factor ratios for D+s→φℓ+νℓ

Physics Letters B, 1999

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

Physics Letters B, 1996

From a sample of 2722 78 + c decaying to the pK + nal state, we have observed, in the hadroproduc... more From a sample of 2722 78 + c decaying to the pK + nal state, we have observed, in the hadroproduction experiment E791 at Fermilab, 143 20 0 c and 122 18 ++ c through their decays to + c. The mass di erence M(0 c) M(+ c) is measured to be (167:38 0:29 0:15) MeV; for M(++ c) M(+ c), we nd (167:76 0:29 0:15) MeV. The rate of + c production from decays of the c triplet is (22 2 3) % of the total + c production assuming equal rate of production from all three, as measured for 0 c and ++ c. We do not observe a statistically signi cant c baryon-antibaryon production asymmetry. The x F and p 2 t spectra of + c from c decays are observed to be similar to those for all + c 's produced.

$Research paper thumbnail of Branching fractions for D0→K+K− and D0→π+π−, and a search for CP violation in D0 decays$

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

Physics Letters B, 1998

J/ψ production via χc decays in 920 GeV pA interactions

Physics Letters B, 2003

Using data collected by the HERA-B experiment, we have measured the fraction of J/ψ's produced vi... more

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

Physics Letters B, 1996

Asymmetries between the production of D + and D − mesons from 500 GeV/c π −-nucleon interactions ... more

Study of the decay D0→K−K+π−π+

Physics Letters B, 1998

Study of theDs+→π−π+π+Decay and Measurement off0Masses and Widths

Physical Review Letters, 2001

From a sample of 848 ± 44 D + s → π − π + π + decays, we find Γ(D + s → π − π + π +)/Γ(D + s → φπ... more From a sample of 848 ± 44 D + s → π − π + π + decays, we find Γ(D + s → π − π + π +)/Γ(D + s → φπ +) = 0.245 ± 0.028 +0.019 −0.012. Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels ρ 0 (770)π + , ρ 0 (1450)π + , f 0 (980)π + , f 2 (1270)π + , and f 0 (1370)π +. We present also the values obtained for masses and widths of the resonances f 0 (980) and f 0 (1370).

Direct Measurement of the Pion Valence-Quark Momentum Distribution, the Pion Light-Cone Wave Function Squared

Physical Review Letters, 2001

We present the first direct measurements of the pion valence quark momentum distribution which is... more

Search forD0D¯0Mixing in Semileptonic Decay Modes

Physical Review Letters, 1996

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

Physical Review Letters, 2001

We report results of a search for flavor-changing neutral current (FCNC), lepton-flavor, and lept... more 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 3 and 4-bodies. Using data from Fermilab charm hadroproduction experiment E791, we examine modes with two leptons (muons or electrons) and either a ρ 0 , K * 0 , or φ vector meson or a non-resonant ππ, Kπ, or KK pair of pseudoscalar mesons. No evidence for any of these decays is found. Therefore, we present branchingfraction upper limits at 90% confidence level for the 27 decay modes examined (18 new).

$Research paper thumbnail of Feynman-x and transverse-momentum dependence of D^{±} and D^{0}, D¯^{0} production in 250 GeV π^{-}-nucleon interactions$

Feynman-x and transverse-momentum dependence of D^{±} and D^{0}, D¯^{0} production in 250 GeV π^{-}-nucleon interactions

Physical Review Letters, 1992

... PM Mantsch, JRT de Mello Neto, J. Metheny, RH Milburn, JM de Miranda, H. da Motta Filho, A. N... more ... PM Mantsch, JRT de Mello Neto, J. Metheny, RH Milburn, JM de Miranda, H. da Motta Filho, A. Napier, AB d&amp;amp;amp;amp;amp;#x27;Olivera, A. Rafatian, AC dos Reis, S. Reucroft, WR Ross, AFS Santoro, M. Sheaff, MHG Souza, WJ Spalding, C. Stoughton, ME Streetman, DJ Summers, S. F Takach, and ...

Erratum: Forward Cross Sections for Production ofD+,D0,Ds,D*+, andΛcin 250 GeVπ±,K±, andpInteractions with Nuclei [Phys. Rev. Lett. 77, 2388 (1996)]

Physical Review Letters, 1998

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

Physical Review Letters, 1998

Measurement of the b anti-b production cross-section in 920-GeV fixed target proton nucleus collisions

DESY-HERA. Measurement of the B-BBAR production cross section in 920 GeV pr oton nuclear collisio... more DESY-HERA. Measurement of the B-BBAR production cross section in 920 GeV pr oton nuclear collisions using carbon and titanium targets. The B-BBAR production is tagged via decays into J/PSI. Both E+ E- and MU+ MU- channels are reconstructed. The data are normalised to a prompt J/PSI production cross section of 357 +- 8 +- 27 nb/nucleon determined from previous measurements rescaled in energy and corrected for atomic number dependence The A dependence of the cross section is taken to be SIG(PA) = A^alpha SIG(PP) with alpha = 0.955 +- 0.005 for the J/PSI production and SIG(PA) = A SIG(PP) for the BBAR production.

Asymmetries in the production of Lambda(c)+ and Lambda(c)- baryons in 500-GeV/c pi- nucleon interactions

FNAL-TEV accelerator. Asymmetries in the production of Lambda/c+ and Lambda/c- baryons in 500-GeV... more

AIP Conference Proceedings, 1992

Fermilab E791, a very high statistics charm particle experiment, recently completed its data taki... more Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.

$Research paper thumbnail of Correlations between D and $${\overline D}$$ mesons produced in 500 GeV/cπ−-nucleon interactions$

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

EPJ direct, 2000

We present a study of correlations between D and D mesons produced in 500 GeV/c π −-nucleon inter... more We present a study of correlations between D and D mesons produced in 500 GeV/c π −-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 Muon Detector at the HERA-B experiment

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2001

The HERA-B experiment is designed to study beauty particle production and decay using the HERA 92... more The HERA-B experiment is designed to study beauty particle production and decay using the HERA 920 GeV proton beam interactions with an internal target. The Muon detector provides identification for muons having momenta greater than 5 GeV/c and triggering on the muon pair from J=c decay. Three different chamber types are employed for operation in a high-rate environment. The overall design, performance and current status are discussed.

Observation of D - π production correlations in 500 GeV π− - N interactions

Physics Letters B, 1997

We study the charge correlations between charm mesons produced in 500 GeV π − − N interactions an... more We study the charge correlations between charm mesons produced in 500 GeV π − − 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 Dπ − 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.

Search for the pentaquark via the decay

Physics Letters B, 1999

Measurement of the form-factor ratios for D+s→φℓ+νℓ

Physics Letters B, 1999

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

Physics Letters B, 1996

From a sample of 2722 78 + c decaying to the pK + nal state, we have observed, in the hadroproduc... more From a sample of 2722 78 + c decaying to the pK + nal state, we have observed, in the hadroproduction experiment E791 at Fermilab, 143 20 0 c and 122 18 ++ c through their decays to + c. The mass di erence M(0 c) M(+ c) is measured to be (167:38 0:29 0:15) MeV; for M(++ c) M(+ c), we nd (167:76 0:29 0:15) MeV. The rate of + c production from decays of the c triplet is (22 2 3) % of the total + c production assuming equal rate of production from all three, as measured for 0 c and ++ c. We do not observe a statistically signi cant c baryon-antibaryon production asymmetry. The x F and p 2 t spectra of + c from c decays are observed to be similar to those for all + c 's produced.

$Research paper thumbnail of Branching fractions for D0→K+K− and D0→π+π−, and a search for CP violation in D0 decays$

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

Physics Letters B, 1998

J/ψ production via χc decays in 920 GeV pA interactions

Physics Letters B, 2003

Using data collected by the HERA-B experiment, we have measured the fraction of J/ψ's produced vi... more

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

Physics Letters B, 1996

Asymmetries between the production of D + and D − mesons from 500 GeV/c π −-nucleon interactions ... more

Study of the decay D0→K−K+π−π+

Physics Letters B, 1998

Study of theDs+→π−π+π+Decay and Measurement off0Masses and Widths

Physical Review Letters, 2001

From a sample of 848 ± 44 D + s → π − π + π + decays, we find Γ(D + s → π − π + π +)/Γ(D + s → φπ... more From a sample of 848 ± 44 D + s → π − π + π + decays, we find Γ(D + s → π − π + π +)/Γ(D + s → φπ +) = 0.245 ± 0.028 +0.019 −0.012. Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels ρ 0 (770)π + , ρ 0 (1450)π + , f 0 (980)π + , f 2 (1270)π + , and f 0 (1370)π +. We present also the values obtained for masses and widths of the resonances f 0 (980) and f 0 (1370).

Direct Measurement of the Pion Valence-Quark Momentum Distribution, the Pion Light-Cone Wave Function Squared

Physical Review Letters, 2001

We present the first direct measurements of the pion valence quark momentum distribution which is... more

Search forD0D¯0Mixing in Semileptonic Decay Modes

Physical Review Letters, 1996

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

Physical Review Letters, 2001

We report results of a search for flavor-changing neutral current (FCNC), lepton-flavor, and lept... more 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 3 and 4-bodies. Using data from Fermilab charm hadroproduction experiment E791, we examine modes with two leptons (muons or electrons) and either a ρ 0 , K * 0 , or φ vector meson or a non-resonant ππ, Kπ, or KK pair of pseudoscalar mesons. No evidence for any of these decays is found. Therefore, we present branchingfraction upper limits at 90% confidence level for the 27 decay modes examined (18 new).

$Research paper thumbnail of Feynman-x and transverse-momentum dependence of D^{±} and D^{0}, D¯^{0} production in 250 GeV π^{-}-nucleon interactions$

Feynman-x and transverse-momentum dependence of D^{±} and D^{0}, D¯^{0} production in 250 GeV π^{-}-nucleon interactions

Physical Review Letters, 1992

... PM Mantsch, JRT de Mello Neto, J. Metheny, RH Milburn, JM de Miranda, H. da Motta Filho, A. N... more ... PM Mantsch, JRT de Mello Neto, J. Metheny, RH Milburn, JM de Miranda, H. da Motta Filho, A. Napier, AB d&amp;amp;amp;amp;amp;#x27;Olivera, A. Rafatian, AC dos Reis, S. Reucroft, WR Ross, AFS Santoro, M. Sheaff, MHG Souza, WJ Spalding, C. Stoughton, ME Streetman, DJ Summers, S. F Takach, and ...

Erratum: Forward Cross Sections for Production ofD+,D0,Ds,D*+, andΛcin 250 GeVπ±,K±, andpInteractions with Nuclei [Phys. Rev. Lett. 77, 2388 (1996)]

Physical Review Letters, 1998

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

Physical Review Letters, 1998