K Baird

Publications (90)129.71 Total impact

• Source

  Available from: Fulvio Galeazzi

  Article: Measurement of branching fractions for exclusive B decays to charmonium final states

  B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, GP Chen, [......], Y Pan, R Prepost, IJ Scott, SJ Sekula, JH von Wimmerspeig-Toeller, SL Wu, Z Yu, H Zobernig, TMB Kordich, H Neal
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  ABSTRACT: We report branching fraction measurements for exclusive decays of charged and neutral B mesons into two-body final states containing a charmonium meson. We use a sample of 22.72±0.36 million BB̅ events collected between October 1999 and October 2000 with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center. The charmonium mesons considered here are J/ψ, ψ(2S), and χc1, and the light meson in the decay is either a K, K*, or π0.
  Physical Review D 02/2013; 65. · 4.56 Impact Factor
• Article: Measurement of the B-0 and B+ meson lifetimes with fully reconstructed hadronic final states

  B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, GP Chen, [......], Y Pan, R Prepost, IJ Scott, SJ Sekula, JH von Wimmersperg-Toeller, SL Wu, Z Yu, H Zobernig, TMB Kordich, H Neal
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  ABSTRACT: The B0 and B+ meson lifetimes have been measured in e+e- annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the ϒ(4S) resonance. Events are selected in which one B meson is fully reconstructed in a hadronic final state while the second B meson is reconstructed inclusively. A combined fit to the B0 and the B+ decay time difference distributions yields τB0 = 1.546±0.032(stat)±0.022(syst) ps, τB+ = 1.673±0.032(stat)±0.023(syst) ps, and τB+/τB0 = 1.082±0.026(stat)±0.012(syst).
  Physical Review Letters 02/2013; 87(20). · 7.37 Impact Factor
• Article: Measurement of D(s)+ and D*(s)+ production in B meson decays and from continuum e+ e- annihilation at s**(1/2) = 10.6-GeV

  BABAR Collaboration, B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, [......], R Liu, Y Pan, R Prepost, IJ Scott, SJ Sekula, JH von Wimmersperg-Toeller, SL Wu, Z Yu, TMB Kordich, H Neal
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  ABSTRACT: New measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the Υ(4S) resonance are presented. Using 20.8 fb-1 of data on the Υ(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the Υ(4S) mass. The branching fractions ΣB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ΣB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.
  Physical Review D 02/2013; 65(9). · 4.56 Impact Factor
• Article: Search for the decay B0→γγ

  B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, GP Chen, [......], R Prepost, IJ Scott, SJ Sekula, JH von Wimmersperg-Toeller, SL Wu, Z Yu, H Zobernig, TMB Kordich, H Neal, BABAR Collaboration
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  ABSTRACT: We report the result of a search for the rare decay B0→γγ in 426  fb-1 of data, corresponding to 226×106 B0B̅ 0 pairs, collected on the Υ(4S) resonance at the PEP-II asymmetric-energy e+e- collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21-12+13 signal events with a statistical significance of 1.8σ. This corresponds to a branching fraction B(B0→γγ)=(1.7±1.1(stat.)±0.2(syst.))×10-7. Based on this result, we set a 90% confidence level upper limit of B(B0→γγ)<3.2×10-7.
  Physical Review D. 01/2011; 83:11.
• Source

  Available from: Piotr Decowski

  Article: Observation of parity nonconservation in møller scattering.

  P L Anthony, R G Arnold, C Arroyo, K Baird, K Bega, J Biesiada, P E Bosted, M Breuer, R Carr, G D Cates, [......], B T Tonguc, J Turner, B Tweedie, A Vacheret, D Walz, T Weber, J Weisend, D Whittum, M Woods, I Younus
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  ABSTRACT: We report a measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV)=[-175+/-30(stat)+/-20(syst)] x 10(-9). This first direct observation of parity nonconservation in Møller scattering leads to a measurement of the electron's weak charge at low energy Q(e)(W)=-0.053+/-0.011. This is consistent with the standard model expectation at the current level of precision: sin((2)theta(W)(M(Z))((-)MS)=0.2293+/-0.0024(stat)+/-0.0016(syst)+/-0.0006(theory).
  Physical Review Letters 06/2004; 92(18):181602. · 7.37 Impact Factor
• Article: Measurement of B --> K*gamma branching fractions and charge asymmetries.

  B Aubert, D Boutigny, J-M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobernig, T M B Kordich, H Neal
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  ABSTRACT: The branching fractions of the exclusive decays B0-->K(*0)gamma and B+-->K(*+)gamma are measured from a sample of (22.74+/-0.36)x10(6) BB decays collected with the BABAR detector at the PEP-II asymmetric e(+)e(-) collider. We find B (B0-->K(*0)gamma) = [4.23+/-0.40(stat)+/-0.22(syst)]x10(-5), B(B+-->K(*+)gamma) = [3.83+/-0.62(stat)+/-0.22(syst)]x10(-5) and constrain the CP-violating charge asymmetry to be -0.170<A(CP)(B-->K(*)gamma)<0.082 at 90% C.L.
  Physical Review Letters 03/2002; 88(10):101805. · 7.37 Impact Factor
• Source

  Available from: Fulvio Galeazzi

  Article: Measurement of the B(0) and B(+) meson lifetimes with fully reconstructed hadronic final states.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobernig, T M Kordich, H Neal
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  ABSTRACT: The B(0) and B(+) meson lifetimes have been measured in e(+)e(-) annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the Upsilon(4S) resonance. Events are selected in which one B meson is fully reconstructed in a hadronic final state while the second B meson is reconstructed inclusively. A combined fit to the B(0) and the B(+) decay time difference distributions yields tau(B(0)) = 1.546+/-0.032(stat)+/-0.022(syst) ps, tau(B(+)) = 1.673+/-0.032(stat)+/-0.023(syst) ps, and tau(B(+))/tau(B(0)) = 1.082+/-0.026(stat)+/-0.012(syst).
  Physical Review Letters 12/2001; 87(20):201803. · 7.37 Impact Factor
• Article: Measurement of the B--> J/psiK*(892) decay amplitudes.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobernig, T M Kordich, H Neal
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  ABSTRACT: We present a measurement of the decay amplitudes in B-->J/psiK*(892) channels using 20.7 fb(-1) of data collected at the Upsilon(4S) resonance with the BABAR detector at PEP-II. We measure a P-wave fraction R(perpendicular) = (16.0 +/- 3.2 +/- 1.4)% and a longitudinal polarization fraction (59.7 +/- 2.8 +/- 2.4)%. The measurement of a relative phase that is neither 0 nor pi, phi = 2.50 +/- 0.20 +/-0.08 radians, favors a departure from the factorization hypothesis. Although the decay B-->/psiK(pi) proceeds mainly via K*(892), there is also evidence for K2*(1430) and K(pi) S-wave contributions.
  Physical Review Letters 12/2001; 87(24):241801. · 7.37 Impact Factor
• Article: Search for the decay B0-->gammagamma.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobernig, T M Kordich, H Neal
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  ABSTRACT: We present a limit on the branching fraction for the decay B0-->gammagamma using data collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric energy e+e- collider. Based on the observation of one event in the signal region, out of a sample of 21.3x10(6) e+e--->Upsilon(4S)-->BB decays, we establish an upper limit on the branching fraction of B(B0-->gammagamma)<1.7x10(-6) at the 90% confidence level. This result substantially improves upon existing limits.
  Physical Review Letters 12/2001; 87(24):241803. · 7.37 Impact Factor
• Article: Measurements of the branching fractions of exclusive charmless B meson decays with eta(') or omega mesons.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobernig, T M Kordich, H Neal
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  ABSTRACT: We present the results of searches for B decays to charmless two-body final states containing eta(') or omega mesons, based on 20.7 fb(-1) of data collected with the BABAR detector. We find the branching fractions Beta(B(+)-->eta(')K(+)) = (70+/-8+/-5) x 10(-6), Beta(B(0)-->eta(')K(0)) = (42(+13)(-11) +/- 4) x 10(-6), and Beta(B(+)-->omega pi(+)) = (6.6(+2.1)(-1.8) +/- 0.7) x 10(-6), where the first error quoted is statistical and the second is systematic. We give measurements of four additional modes for which the 90% confidence level upper limits are Beta(B(+)-->eta(')pi(+)) < 12 x 10(-6), Beta(B(+)-->omega K(+)) < 4 x 10(-6), Beta(B(0)-->omega K(0)) < 13 x 10(-6), and Beta(B(0)-->omega pi(0)) < 3 x 10(-6).
  Physical Review Letters 11/2001; 87(22):221802. · 7.37 Impact Factor
• Source

  Available from: Fulvio Galeazzi

  Article: Measurement of branching fractions and search for CP-violating charge asymmetries in charmless two-body B decays into pions and kaons.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobering, T M Kordich, H Neal
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  ABSTRACT: We present measurements, based on a sample of approximately 23x10(6) BB pairs, of the branching fractions and a search for CP-violating charge asymmetries in charmless hadronic decays of B mesons into two-body final states of kaons and pions. We find the branching fractions B(B0-->pi(+)pi(-)) = (4.1+/-1.0+/-0.7)x10(-6), B(B0-->K+pi(-)) = (16.7+/-1.6+/-1.3)x10(-6), B(B+-->K+pi(0)) = (10.8(+2.1)(-1.9)+/-1.0)x10(-6), B(B+-->K0pi(+)) = (18.2(+3.3)(-3.0)+/-2.0)x10(-6), B(B0-->K0pi(0)) = (8.2(+3.1)(-2.7)+/-1.2)x10(-6). We also report 90% confidence level upper limits for B meson decays to the pi(+)pi(0), K+K-, and K0K+ final states. In addition, charge asymmetries have been found to be consistent with zero, where the statistical precision is in the range of +/-0.10 to +/-0.18, depending on the decay mode.
  Physical Review Letters 10/2001; 87(15):151802. · 7.37 Impact Factor
• Article: Measurement of the decays B--> phiK and B--> phiK*.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobering, T M Kordich, H Neal
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  ABSTRACT: We have observed the decays B--> phiK and phiK(*) in a sample of over 45 million B mesons collected with the BABAR detector at the PEP-II collider. The measured branching fractions are B(B+--> phiK+) = (7.7(+1.6)(-1.4)+/-0.8)x10(-6), B(B0--> phiK0) = (8.1(+3.1)(-2.5)+/-0.8)x10(-6), B(B+--> phiK(*+)) = (9.7(+4.2)(-3.4)+/-1.7)x10(-6), and B(B0--> phiK(*0)) = (8.7(+2.5)(-2.1)+/-1.1)x10(-6). We also report the upper limit B(B+--> phipi(+))<1.4x10(-6) ( 90% C.L.).
  Physical Review Letters 10/2001; 87(15):151801. · 7.37 Impact Factor
• Article: Measurement of J/psi production in continuum e(+)e(-) annihilations near square root of s = 10.6 GeV.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobernig, T M Kordich, H Neal
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  ABSTRACT: The production of J/psi mesons in continuum e(+)e(-) annihilations has been studied with the BABAR detector at energies near the Upsilon(4S) resonance. The mesons are distinguished from J/psi production in B decays through their center-of-mass momentum and energy. We measure the cross section e(+)e(-)-->J/psi X to be 2.52+/-0.21+/-0.21 pb. We set a 90% C.L. upper limit on the branching fraction for direct Upsilon(4S)-->J/psi X decays at 4.7 x 10(-4).
  Physical Review Letters 10/2001; 87(16):162002. · 7.37 Impact Factor
• Source

  Available from: Fulvio Galeazzi

  Article: Observation of CP violation in the B(0) meson system.

  B Aubert, D Boutigny, J M Gaillard, A Hicheur, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, G P Chen, [......], J Nielsen, Y Pan, R Prepost, I J Scott, S J Sekula, J H von Wimmersperg-Toeller, S L Wu, H Zobernig, T M Kordich, H Neal
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  ABSTRACT: We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.
  Physical Review Letters 09/2001; 87(9):091801. · 7.37 Impact Factor
• Source

  Available from: Filippo Bosi

  Article: Measurement of CP-violating asymmetries in B0 decays to CP eigenstates.

  B Aubert, D Boutigny, I De Bonis, J M Gaillard, A Jeremie, Y Karyotakis, J P Lees, P Robbe, V Tisserand, A Palano, [......], Y Pan, R Prepost, I J Scott, J H von Wimmersperg-Toeller, S L Wu, Z Yu, H Zobernig, T M Kordich, T B Moore, H Neal
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  ABSTRACT: We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23x10(6) Upsilon(4S)-->BbarB decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events in which one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta = 0.34+/-0.20 (stat)+/-0.05 (syst).
  Physical Review Letters 03/2001; 86(12):2515-22. · 7.37 Impact Factor
• Article: Measurement of the branching fractions for ψ(2S)→e+e- and ψ(2S)→μ+μ-

  B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, A Pompili, [......], Y Pan, R Prepost, IJ Scott, SJ Sekula, JH von Wimmersperg-Toeller, SL Wu, Z Yu, TMB Kordich, H Neal, BABAR Collaboration
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  ABSTRACT: We measure the branching fractions of the ψ(2S) meson to the leptonic final states e+e- and μ+μ- relative to that for ψ(2S)→J/ψπ+π-. The method uses ψ(2S) mesons produced in the decay of B mesons at the Υ(4S) resonance in a data sample collected with the BABAR detector at the Stanford Linear Accelerator Center. Using previous measurements for the ψ(2S)→J/ψπ+π- branching fraction, we determine the e+e-and μ+μ- branching fractions to be 0.0078±0.0009±0.0008 and 0.0067±0.0008±0.0007, respectively.
  Physical Review D 01/2001; 65. · 4.56 Impact Factor
• Article: Search for the decay B-0 ->gamma gamma

  B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, GP Chen, [......], R Prepost, IJ Scott, SJ Sekula, JH von Wimmersperg-Toeller, SL Wu, Z Yu, H Zobernig, TMB Kordich, H Neal, BABAR Collaboration
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  ABSTRACT: We present a limit on the branching fraction for the decay B0→γγ using data collected at the ϒ(4S) resonance with the BABAR detector at the PEP-II asymmetric energy e+e- collider. Based on the observation of one event in the signal region, out of a sample of 21.3×106 e+e-→ϒ(4S)→BB̅ decays, we establish an upper limit on the branching fraction of B(B0→γγ)<1.7×10-6 at the 90% confidence level. This result substantially improves upon existing limits.
  Physical Review Letters 01/2001; 87. · 7.37 Impact Factor
• Article: Measurement of the decays B ->phi K and B ->phi K*

  B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, GP Chen, [......], W Orejudos, Y Pan, R Prepost, IJ Scott, SJ Sekula, JH von Wimmersperg-Toeller, SL Wu, Z Yu, H Zobernig, BABAR Collaboration
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  ABSTRACT: We have observed the decays B→φK and φK* in a sample of over 45 million B mesons collected with the BABAR detector at the PEP-II collider. The measured branching fractions are B(B+→φK+) = (7.7-1.4+1.6±0.8)×10-6, B(B0→φK0) = (8.1-2.5+3.1±0.8)×10-6, B(B+→φK*+) = (9.7-3.4+4.2±1.7)×10-6, and B(B0→φK*0) = (8.7-2.1+2.5±1.1)×10-6. We also report the upper limit B(B+→φπ+)<1.4×10-6 ( 90% C.L.).
  Physical Review Letters 01/2001; 87:7. · 7.37 Impact Factor
• Conference Proceeding: Design, construction and first operation of the large CsIcalorimeter for the BaBar detector at the PEP-II storage rings

  J Allison, K Baird, R J Barlow, J M Bauer, R Bernet, M Booke, C K Bowdery, T Brandt, A Brooks, J Brose, [......], P. Vidal, R Waldi, D. Walz, R Wang, M Weaver, W J Wisniewski, C R Wuest, D S Yan, Y Xue, R Y Zhu
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  ABSTRACT: The design and construction of the BaBar electromagnetic calorimeter are reviewed. Recent results on the expected sensitivity of the CsI(TI) to radiation damage are discussed. The performance of the calorimeter in the first PEP-II run is presented. Particular emphasis is placed on operational experience and the measured degradation due to radiation damage. Correlation of radiation damage with the dose recorded in a novel large-scale array of radiation sensitive FETs are presented. The consequences for the long-term performance of a CsI(TI) calorimeter operating in a high background environment are discussed
  Nuclear Science Symposium, 1999. Conference Record. 1999 IEEE; 02/1999
• Article: Neutron scattering from 12C between 15.6 and 17.3 MeV

  Z M Chen, K Baird, C R Howell, M L Roberts, W Tornow, R L Walter
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  ABSTRACT: The differential cross section sigma ( theta ) for neutron elastic scattering from 12C and for inelastic scattering from the 4.44 MeV state was measured at 15.57, 16.75 and 17.29 MeV. The sigma ( theta ) data, together with published analysing power Ay( theta ) data, were analysed in the framework of the spherical optical model and in the coupled-channels formalism. It was concluded that the present 12C(n,n)12C data and published data at higher energies appear to be well suited for determining properties of valence single-particle excitations in 11C and 13C via an iterative-moment approach or a dispersive optical-model analysis.
  Journal of Physics G Nuclear and Particle Physics 12/1998; 19(6):877. · 4.18 Impact Factor