W Toki

Publications (65)62.73 Total impact

• Source

  Available from: Lucio Ludovici

  Article: Measurement of the Inclusive NuMu Charged Current Cross Section on Carbon in the Near Detector of the T2K Experiment

  K. Abe, N. Abgrall, H. Aihara, T. Akiri, J. B. Albert, C. Andreopoulos, S. Aoki, A. Ariga, T. Ariga, S. Assylbekov, [......], N. Yershov, M. Yokoyama, ̇ T. Yuan, A. Zalewska, L. Zambelli, K. Zaremba, M. Ziembicki, E. D. Zimmerman, M. Zito, and J. Zmuda
  [show abstract] [hide abstract]
  ABSTRACT: T2K has performed the first measurement of \nu{\mu} inclusive charged current interactions on carbon at neutrino energies of ~1 GeV where the measurement is reported as a flux-averaged double differential cross section in muon momentum and angle. The flux is predicted by the beam Monte Carlo and external data, including the results from the NA61/SHINE experiment. The data used for this measurement were taken in 2010 and 2011, with a total of 10.8 x 10^{19} protons-on-target. The analysis is performed on 4485 inclusive charged current interaction candidates selected in the most upstream fine-grained scintillator detector of the near detector. The flux-averaged total cross section is <\sigma_CC>_\phi =(6.91 +/- 0.13 (stat) +/- 0.84 (syst)) x10^{-39} cm^2/nucleon for a mean neutrino energy of 0.85 GeV.
  02/2013;
• Article: The T2K Neutrino Flux Prediction

  Collaboration, K. Abe, N. Abgrall, H. Aihara, T. Akiri, J. B. Albert, C. Andreopoulos, S. Aoki, A. Ariga, T. Ariga, [......], N. Yershov, M. Yokoyama, T. Yuan, A. Zalewska, L. Zambelli, K. Zaremba, M. Ziembicki, E. D. Zimmerman, M. Zito, J. Zmuda
  [show abstract] [hide abstract]
  ABSTRACT: The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an off-axis muon neutrino beam with a peak energy of about 0.6 GeV that originates at the J-PARC accelerator facility. Interactions of the neutrinos are observed at near detectors placed at 280 m from the production target and at the far detector -- Super-Kamiokande (SK) -- located 295 km away. The flux prediction is an essential part of the successful prediction of neutrino interaction rates at the T2K detectors and is an important input to T2K neutrino oscillation and cross section measurements. A FLUKA and GEANT3 based simulation models the physical processes involved in the neutrino production, from the interaction of primary beam protons in the T2K target, to the decay of hadrons and muons that produce neutrinos. The simulation uses proton beam monitor measurements as inputs. The modeling of hadronic interactions is re-weighted using thin target hadron production data, including recent charged pion and kaon measurements from the NA61/SHINE experiment. For the first T2K analyses the uncertainties on the flux prediction are evaluated to be below 15% near the flux peak. The uncertainty on the ratio of the flux predictions at the far and near detectors is less than 2% near the flux peak.
  11/2012;
• Source

  Available from: Peter. Gumplinger

  Article: First Muon-Neutrino Disappearance Study with an Off-Axis Beam

  Collaboration, K. Abe, N. Abgrall, Y. Ajima, H. Aihara, J. B. Albert, C. Andreopoulos, B. Andrieu, M. D. Anerella, S. Aoki, [......], M. Yokoyama, T. Yuan, A. Zalewska, J. Zalipska, L. Zambelli, K. Zaremba, M. Ziembicki, E. D. Zimmerman, M. Zito, J. Zmuda
  [show abstract] [hide abstract]
  ABSTRACT: We report a measurement of muon-neutrino disappearance in the T2K experiment. The 295-km muon-neutrino beam from Tokai to Kamioka is the first implementation of the off-axis technique in a long-baseline neutrino oscillation experiment. With data corresponding to 1.43 10**20 protons on target, we observe 31 fully-contained single muon-like ring events in Super-Kamiokande, compared with an expectation of 104 +- 14 (syst) events without neutrino oscillations. The best-fit point for two-flavor nu_mu -> nu_tau oscillations is sin**2(2 theta_23) = 0.98 and |\Delta m**2_32| = 2.65 10**-3 eV**2. The boundary of the 90 % confidence region includes the points (sin**2(2 theta_23),|\Delta m**2_32|) = (1.0, 3.1 10**-3 eV**2), (0.84, 2.65 10**-3 eV**2) and (1.0, 2.2 10**-3 eV**2).
  01/2012;
• Source

  Available from: Istvan Danko

  Article: The T2K ND280 Off-Axis Pi-Zero Detector

  S. Assylbekov, B. E. Berger, H. Berns, D. Beznosko, A. Bodek, R. Bradford, N. Buchanan, H. Budd, Y. Caffari, K. Connolly, [......], A. S. Tadepalli, I. J. Taylor, W. Toki, C. Vanek, D. Warner, A. Weber, R. J. Wilkes, R. J. Wilson, C. Yanagisawa, T. Yuan
  [show abstract] [hide abstract]
  ABSTRACT: The Pi-Zero detector (P{\O}D) is one of the subdetectors that makes up the off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino experiment. The primary goal for the P{\O}D is to measure the relevant cross sections for neutrino interactions that generate pi-zero's, especially the cross section for neutral current pi-zero interactions, which are one of the dominant sources of background to the electron neutrino appearance signal in T2K. The P{\O}D is composed of layers of plastic scintillator alternating with water bags and brass sheets or lead sheets and is one of the first detectors to use Multi-Pixel Photon Counters (MPPCs) on a large scale.
  11/2011;
• Source

  Available from: Peter. Gumplinger

  Article: Measurements of the T2K neutrino beam properties using the INGRID on-axis near detector

  K Abe, N. Abgrall, Y. Ajima, H. Aihara, J. B. Albert, C. Andreopoulos, B Andrieu, M. D. Anerella, S Aoki, O. Araoka, [......], M Yokoyama, T Yuan, A Zalewska, J. Zalipska, L. Zambelli, K Zaremba, M Ziembicki, E. D. Zimmerman, M Zito, J. Zmuda
  [show abstract] [hide abstract]
  ABSTRACT: Precise measurement of neutrino beam direction and intensity was achieved based on a new concept with modularized neutrino detectors. INGRID (Interactive Neutrino GRID) is an on-axis near detector for the T2K long baseline neutrino oscillation experiment. INGRID consists of 16 identical modules arranged in horizontal and vertical arrays around the beam center. The module has a sandwich structure of iron target plates and scintillator trackers. INGRID directly monitors the muon neutrino beam profile center and intensity using the number of observed neutrino events in each module. The neutrino beam direction is measured with accuracy better than 0.4 mrad from the measured profile center. The normalized event rate is measured with 4% precision.
  11/2011;
• Source

  Available from: Steve Kettell

  Article: The 2010 Interim Report of the Long-Baseline Neutrino Experiment Collaboration Physics Working Groups

  The LBNE Collaboration, T. Akiri, D. Allspach, M. Andrews, K Arisaka, E. Arrieta-Diaz, M. Artuso, X Bai, B. Balantekin, B. Baller, [......], W. Willis, R J Wilson, L. Winslow, J Ye, M Yeh, B Yu, G. Zeller, C Zhang, E Zimmerman, R. Zwaska
  [show abstract] [hide abstract]
  ABSTRACT: In early 2010, the Long-Baseline Neutrino Experiment (LBNE) science collaboration initiated a study to investigate the physics potential of the experiment with a broad set of different beam, near- and far-detector configurations. Nine initial topics were identified as scientific areas that motivate construction of a long-baseline neutrino experiment with a very large far detector. We summarize the scientific justification for each topic and the estimated performance for a set of far detector reference configurations. We report also on a study of optimized beam parameters and the physics capability of proposed Near Detector configurations. This document was presented to the collaboration in fall 2010 and updated with minor modifications in early 2011.
  10/2011;
• Source

  Available from: Peter. Gumplinger

  Article: Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam.

  K Abe, N Abgrall, Y Ajima, H Aihara, J B Albert, C Andreopoulos, B Andrieu, S Aoki, O Araoka, J Argyriades, [......], N Yershov, M Yokoyama, A Zalewska, J Zalipska, L Zambelli, K Zaremba, M Ziembicki, E D Zimmerman, M Zito, J Żmuda
  [show abstract] [hide abstract]
  ABSTRACT: The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.
  Physical Review Letters 07/2011; 107(4):041801. · 7.37 Impact Factor
• Source

  Available from: Peter. Gumplinger

  Article: The T2K Experiment

  Collaboration, N. Abgrall, H. Aihara, Y. Ajima, J. B. Albert, D. Allan, P. -A. Amaudruz, C. Andreopoulos, B. Andrieu, M. D. Anerella, [......], S. Yen, N. Yershov, M. Yokoyama, A. Zalewska, J. Zalipska, K. Zaremba, M. Ziembicki, E. D. Zimmerman, M. Zito, J. Zmuda
  [show abstract] [hide abstract]
  ABSTRACT: The T2K experiment is a long-baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle {\theta}_{13} by observing {\nu}_e appearance in a {\nu}_{\mu} beam. It also aims to make a precision measurement of the known oscillation parameters, {\Delta}m^{2}_{23} and sin^{2} 2{\theta}_{23}, via {\nu}_{\mu} disappearance studies. Other goals of the experiment include various neutrino cross section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem.
  06/2011;
• Source

  Available from: Eleonora Luppi

  Article: Search for a low-mass higgs boson in Upsilon(3S)-->gammaA(0), A(0)-->tau(+)tau(-) at BABAR.

  B Aubert, Y Karyotakis, J P Lees, V Poireau, E Prencipe, X Prudent, V Tisserand, J Garra Tico, E Grauges, M Martinelli, [......], G B Mohanty, E M T Puccio, H R Band, X Chen, S Dasu, K T Flood, Y Pan, R Prepost, C O Vuosalo, S L Wu
  [show abstract] [hide abstract]
  ABSTRACT: We search for a light Higgs boson A0 in the radiative decay Upsilon(3S)-->gammaA(0), A(0)-->tau+tau-, tau+-->e+nu(e)nu(tau), or tau+-->mu+nu(mu)nu(tau). The data sample contains 122x10(6) Upsilon(3S) events recorded with the BABAR detector. We find no evidence for a narrow structure in the studied tau+tau- invariant mass region of 4.03<m(tau+tau-)<10.10 GeV/c2. We exclude at the 90% confidence level (C.L.) a low-mass Higgs boson decaying to tau+tau- with a product branching fraction B(Upsilon(3S)-->gammaA(0))xB(A(0)-->tau+tau-)>(1.5-16)x10(-5) across the m(tau+tau-) range. We also set a 90% C.L. upper limit on the tau+tau- decay of the eta(b) at B(eta(b)-->tau+tau-)<8%.
  Physical Review Letters 10/2009; 103(18):181801. · 7.37 Impact Factor
• Article: Search for second-class currents in tau;{-} --> omegapi;{-}nu_{tau}.

  B Aubert, Y Karyotakis, J P Lees, V Poireau, E Prencipe, X Prudent, V Tisserand, J Garra Tico, E Grauges, M Martinelli, [......], G B Mohanty, E M T Puccio, H R Band, X Chen, S Dasu, K T Flood, Y Pan, R Prepost, C O Vuosalo, S L Wu
  [show abstract] [hide abstract]
  ABSTRACT: We report an analysis of tau;{-} decaying into omegapi;{-}nu_{tau} with omega --> pi;{+}pi;{-}pi;{0} using a data sample containing nearly 320 x 10;{6}tau pairs collected with the BABAR detector at the PEP-II B-Factory. We find no evidence for second-class currents, and we set an upper limit of 0.69% at 90% confidence level for the fraction of second-class currents in this decay mode.
  Physical Review Letters 07/2009; 103(4):041802. · 7.37 Impact Factor
• Article: Evidence for X(3872)-->psi(2S)gamma in B(+/-)-->X(3872)K(+/-) decays and a study of B-->cc[over ]gammaK.

  B Aubert, M Bona, Y Karyotakis, J P Lees, V Poireau, E Prencipe, X Prudent, V Tisserand, J Garra Tico, E Grauges, [......], G B Mohanty, H R Band, X Chen, S Dasu, K T Flood, Y Pan, M Pierini, R Prepost, C O Vuosalo, S L Wu
  [show abstract] [hide abstract]
  ABSTRACT: In a search for B-->cc[over ]gammaK decays with the BABAR detector, where cc[over ] includes J/psi and psi(2S), and K includes K(+/-), K(S)(0), and K(*)(892), we find evidence for X(3872)-->J/psigamma and X(3872)-->psi(2S)gamma with 3.6sigma and 3.5sigma significance, respectively. We measure the product of branching fractions B(B(+/-)-->X(3872)K(+/-))xB(X(3872)-->J/psigamma)=[2.8+/-0.8(stat)+/-0.1(syst)]x10(-6) and B(B(+/-)-->X(3872)K(+/-))xB(X(3872)-->psi(2S)gamma)=[9.5+/-2.7(stat)+/-0.6(syst)]x10(-6).
  Physical Review Letters 05/2009; 102(13):132001. · 7.37 Impact Factor
• Article: CP-violation parameters from decay rates of B^{±}→ DK^{±}, D→ multibody final states

  A. Soffer, W. Toki, F. Winklmeier
  [show abstract] [hide abstract]
  ABSTRACT: We describe a method for measuring CP-violation parameters from which the Cabibbo-Kobayashi-Maskawa angle γ may be extracted. The method makes use of the total decay rates in B±→DK± decays, where the neutral D meson decays to multibody final states. We analyze the error of the method using experimental CP-violation analysis variables that enable straightforward sensitivity comparison with other methods for extracting γ, and discuss the use of B-factory and charm-factory data to obtain the relevant charm-decay information needed for this measurement. Measurement sensitivities are estimated for the currently available B-factory data sample, and D decay modes for which use of this method can make a significant contribution toward reducing the total error on γ are identified.
  Phys. Rev. D. 01/2009; 79(1).
• Source

  Available from: Shahriar Abachi

  Article: Measurement of the branching fractions of B-->D**(l) nu(l) decays in events tagged by a fully reconstructed B meson.

  B Aubert, M Bona, Y Karyotakis, J P Lees, V Poireau, E Prencipe, X Prudent, V Tisserand, J Garra Tico, E Grauges, [......], G B Mohanty, H R Band, X Chen, S Dasu, K T Flood, Y Pan, M Pierini, R Prepost, C O Vuosalo, S L Wu
  [show abstract] [hide abstract]
  ABSTRACT: We report a measurement of the branching fractions of B-->D**(l) nu(l), decays based on 417 fb(-1) of data collected at the Y(4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. Events are selected by full reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m(D(*) pi)- m(D(*)) is performed to extract the signal yields of the different D** states. We observe the B-->D**l(-1)nu(l) decay modes corresponding to the four D states predicted by heavy quark symmetry with a significance greater than 5 standard deviations including systematic uncertainties.
  Physical Review Letters 12/2008; 101(26):261802. · 7.37 Impact Factor
• Article: Measurement of the CP asymmetry in b-->sgamma using a sum of exclusive final states.

  B Aubert, M Bona, Y Karyotakis, J P Lees, V Poireau, X Prudent, V Tisserand, A Zghiche, J Garra Tico, E Grauges, [......], H R Band, X Chen, S Dasu, K T Flood, P E Kutter, Y Pan, M Pierini, R Prepost, C O Vuosalo, S L Wu
  [show abstract] [hide abstract]
  ABSTRACT: We perform a measurement of the CP asymmetry in b-->sgamma decays using a sample of 383 x 10(6) B[over] B events collected by the BABAR detector at the SLAC PEP-II asymmetric B factory. We reconstruct 16 flavor-specific B decay modes containing a high-energy photon and a hadronic system X_(s) containing an s quark. We measure the CP asymmetry to be -0.011+/-0.030(stat)+/-0.014(syst) for a hadronic system mass between 0.6 and 2.8 GeV/c(2).
  Physical Review Letters 10/2008; 101(17):171804. · 7.37 Impact Factor
• Chapter: Evidence for 2γ processes at the ISR

  F. Vannucci, CERN-Harvard-LAPP-MIT-Naples-Pisa Collaboration, D. Antreasyan, W. Atwood, R. Battiston, U. Becker, G. Bellettini, P. L. Braccini, J. G. Branson, J. Burger, [......], G. Sanguinetti, C. Sciacca, M. Steuer, K. Strauch, S. Sugimoto, S. C. C. Ting, W. Toki, M. Valdata-Nappi, C. Vannini, F. Visco
  [show abstract] [hide abstract]
  ABSTRACT: Studying the reaction Studyingpp + –X at the Intersecting Storage Rings (ISR),a special class of events was found for which no hadrons are seen associated with the muon pair in a large solid angle vertex detector. The origin of these events can be most naturally explained as arising from the two-photon process in pp collisions. It is emphasized that this process becomes increasingly interesting at higher hadron colliding facilities.
  01/2006: pages 238-247;
• Article: Observation of a near-threshold enhancement in the pp mass spectrum from radiative J/psi-->gammapp decays.

  J Z Bai, Y Ban, J G Bian, X Cai, J F Chang, H F Chen, H S Chen, J Chen, Jie Chen, J C Chen, [......], L Zhou, N F Zhou, K J Zhu, Q M Zhu, Yingchun Zhu, Y C Zhu, Y S Zhu, Z A Zhu, B A Zhuang, B S Zou
  [show abstract] [hide abstract]
  ABSTRACT: We observe a narrow enhancement near 2m(p) in the invariant mass spectrum of pp pairs from radiative J/psi-->gammapp decays. No similar structure is seen in J/psi-->pi(0)pp decays. The results are based on an analysis of a 58 x 10(6) event sample of J/psi decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit-Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m(p) at M=1859(+3)(-10) (stat)+5-25(syst) MeV/c(2) and the total width is Gamma<30 MeV/c(2) at the 90% confidence level. These mass and width values are not consistent with the properties of any known particle.
  Physical Review Letters 07/2003; 91(2):022001. · 7.37 Impact Factor
• Article: ψ(2S) two- and three-body hadronic decays

  J. Z. Bai, Y. Ban, J. G. Bian, I. Blum, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, J. Chen, Jie Chen, [......], B. Q. Zhou, G. M. Zhou, L. Zhou, K. J. Zhu, Q. M. Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
  [show abstract] [hide abstract]
  ABSTRACT: We report measurements of branching fractions for ψ(2S) decays into ωπ+π-, b1π, ωf2(1270), ωK+K-, ωpp̅ , φπ+π-, φf0(980), φK+K-, and an upper limit for φpp̅ final states based on a data sample of (4.02±0.22)×106ψ(2S) events collected with the BESI detector at the Beijing Electron-Positron Collider. The branching fractions for b1π and ωf2(1270) update previous BES results, while those for other decay modes are first measurements. The ratios of ψ(2S) and J/ψ branching fractions are smaller than what is expected from the 12% rule by a factor of 5 for ωf2(1270) and by a factor of 2 for ωπ+π-, ωpp̅ , and φK+K-, while for other studied channels the ratios are consistent with expectations within errors.
  Phys. Rev. D. 03/2003; 67(5).
• Source

  Available from: Jian Guo Bian

  Article: Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV.

  J Z Bai, Y Ban, J G Bian, A D Chen, H F Chen, H S Chen, J C Chen, X D Chen, Y B Chen, B S Cheng, [......], B Q Zhou, G M Zhou, L Zhou, K J Zhu, Q M Zhu, Y C Zhu, Y S Zhu, Z A Zhu, B A Zhuang, B S Zou
  [show abstract] [hide abstract]
  ABSTRACT: We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.
  Physical Review Letters 03/2002; 88(10):101802. · 7.37 Impact Factor
• Article: Measurement of ψ(2S) decays to baryon pairs

  J. Z. Bai, Y. Ban, J. G. Bian, I. Blum, A. D. Chen, G. P. Chen, H. F. Chen, H. S. Chen, J. Chen, J. C. Chen, [......], L. S. Zheng, Z. P. Zheng, B. Q. Zhou, L. Zhou, K. J. Zhu, Q. M. Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang
  [show abstract] [hide abstract]
  ABSTRACT: A sample of 3.95M ψ(2S) decays registered in the BES detector are used to study final states containing pairs of octet and decuplet baryons. We report branching fractions for ψ(2S)→pp̅ , ΛΛ̅ , Σ0Σ̅ 0, Ξ-Ξ̅ +, Δ++Δ̅ --, Σ+(1385)Σ̅ -(1385), Ξ0(1530)Ξ̅ 0(1530), and Ω-Ω̅ +. These results are compared to expectations based on the SU(3)-flavor symmetry, factorization, and perturbative QCD.
  Phys. Rev. D. 01/2001; 63(3).
• Article: Measurement of the mass and full width of the ηc meson

  J. Z. Bai, Y. Ban, J. G. Bian, I. Blum, A. D. Chen, G. P. Chen, H. F. Chen, H. S. Chen, J. Chen, J. C. Chen, [......], Y. H. Zheng, Z. P. Zheng, B. Q. Zhou, L. Zhou, K. J. Zhu, Q. M. Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang
  [show abstract] [hide abstract]
  ABSTRACT: In a sample of 7.8 million J/ψ decays collected in the Beijing Spectrometer, the process J/ψ⃗γηc is observed for five different ηc decay channels: K+K-π+π-, π+π-π+π-, K±KS0π∓ (with KS0→π+π-), φφ (with φ⃗K+K-) and K+K-π0. From these signals, we determine the mass of ηc to be 2976.6±2.9±1.3 MeV. Combining this result with a previously reported result from a similar study using ψ(2S)→γηc detected in the same spectrometer gives mηc=2976.3±2.3±1.2 MeV. For the combined samples, we obtain Γηc=11.0±8.1±4.1 MeV.
  Phys. Rev. D. 08/2000; 62(7).