P Del Amo Sanchez

Publications (350)682.22 Total impact

• Article: Observation and study of the baryonic B-meson decays B→D(*)pp̅ (π)(π)

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We present results for B-meson decay modes involving a charm meson, protons, and pions using 455×106 BB̅ pairs recorded by the BaBar detector at the SLAC PEP-II asymmetric-energy e+e- collider. The branching fractions are measured for the following ten decays: B̅ 0→D0pp̅ , B̅ 0→D*0pp̅ , B̅ 0→D+pp̅ π-, B̅ 0→D*+pp̅ π-, B-→D0pp̅ π-, B-→D*0pp̅ π-, B̅ 0→D0pp̅ π-π+, B̅ 0→D*0pp̅ π-π+, B-→D+pp̅ π-π-, and B-→D*+pp̅ π-π-. The four B- and the two five-body B̅ 0 modes are observed for the first time. The four-body modes are enhanced compared to the three- and the five-body modes. In the three-body modes, the M(pp̅ ) and M(D(*)0p) invariant-mass distributions show enhancements near threshold values. In the four-body mode B̅ 0→D+pp̅ π-, the M(pπ-) distribution shows a narrow structure of unknown origin near 1.5 GeV/c2. The distributions for the five-body modes, in contrast to the others, are similar to the expectations from uniform phase-space predictions.
  Phys. Rev. D. 05/2012; 85(9).
• Article: Momentum measurement by the multiple Coulomb scattering method in the OPERA lead-emulsion target

  N Agafonova, A Aleksandrov, O Altinok, A Anokhina, S Aoki, A Ariga, T Ariga, D Autiero, A Badertscher, A Bagulya, [......], G Wilquet, B Wonsak, V Yakushev, C S Yoon, T Yoshioka, J Yoshida, Y Zaitsev, S Zemskova, A Zghiche, R Zimmermann
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  ABSTRACT: A new method of momentum measurement of charged particles through multiple Coulomb scattering (MCS) in the OPERA lead-emulsion target is presented. It is based on precise measurements of track angular deviations carried out thanks to the very high resolution of nuclear emulsions. The algorithm has been tested with Monte Carlo pions. The results are found to describe within the expected uncertainties the data obtained from test beams. We also present a comparison of muon momenta evaluated through MCS in the OPERA lead-emulsion target with those determined by the electronic detectors for neutrino-charged current interaction events. The two independent measurements agree within the experimental uncertainties, and the results validate the algorithm developed for the emulsion detector of OPERA.
  New Journal of Physics 01/2012; 14(1):013026. · 4.18 Impact Factor
• Article: Measurement of $D^0-overline{D}^0$ mixing parameters using $D^0 \to K_S^0 \pi^ \pi^-$ and $D^0 \to K_S^0 K^ K^-$ decays

  P. del Amo Sanchez, J.P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], B. Stugu, L. Sun, M. Battaglia, D.N. Brown, B. Hooberman, L.T. Kerth, Yu.G. Kolomensky, G. Lynch, I.L. Osipenkov, T. Tanabe
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  ABSTRACT: We report a direct measurement of D{sup 0}-{bar D}{sup 0} mixing parameters through a time-dependent amplitude analysis of the Dalitz plots of D{sup 0} {yields} K{sub S}{sup 0}{pi}{sup +}{pi}{sup -} and, for the first time, D{sup 0} {yields} K{sub S}{sup 0}K{sup +}K{sup -} decays. The low-momentum pion {pi}{sub s}{sup +} in the decay D*{sup +} {yields} D{sup 0}{pi}{sub s}{sup +} identifies the flavor of the neutral D meson at its production. Using 468.5 fb{sup -1} of e{sup +}e{sup -} colliding-beam data recorded near {radical}s = 10.6 GeV by the BABAR detector at the PEP-II asymmetric-energy collider at SLAC, we measure the mixing parameters x = [1.6 {+-} 2.3 (stat.) {+-} 1.2 (syst.) {+-} 0.8 (model)] x 10{sup -3}, and y = [5.7 {+-} 2.0 (stat.) {+-} 1.3 (syst.) {+-} 0.7 (model)] x 10{sup -3}. These results provide the best measurement to date of x and y. The knowledge of the value of x, in particular, is crucial for understanding the origin of mixing.
  Phys.Rev.Lett.105:081803,2010. 08/2011;
• Article: Measurement of the B0 ->&#960&#8722&#8467&#957and B ->&#951(&#8242)&#8467&#957Branching Fractions, the B0 ->&#960&#8722&#8467&#957and B ->&#951&#8467&#957Form-Factor Shapes, and Determination of |Vub|

  P. del Amo Sanchez, J.P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D.A. Milanes, A. Palano, [......], G. Eigen, B. Stugu, L. Sun, D.N. Brown, L.T. Kerth, Yu.G. Kolomensky, G. Lynch, I.L. Osipenkov, H. Koch, T. Schroeder
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  ABSTRACT: We report the results of a study of the exclusive charmless semileptonic decays, B{sup +} {yields} {eta}{sup {prime}}{ell}{sup +}{nu} and B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}, undertaken with approximately 464 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B{sup +} {yields} {eta}{ell}{sup +}{nu} and B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} decays in three and 12 bins of q{sup 2}, respectively, from which we extract the f{sub +}(q{sup 2}) form-factor shapes and the total branching fractions {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) = (0.36 {+-} 0.05{sub stat} {+-} 0.04{sub syst}) x 10{sup -4} and {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.42 {+-} 0.05{sub stat} {+-} 0.07{sub syst}) x 10{sup -4}. We also measure {Beta}(B{sup +} {yields} {eta}{sup {prime}}{ell}{sup +}{nu}) = (0.24 {+-} 0.08{sub stat} {+-} 0.03{sub syst}) x 10{sup -4}. We obtain values for the magnitude of the CKM matrix element |V{sub ub}| using three different QCD calculations.
  Phys.Rev.D83:052011,2011. 08/2011; 83(5).
• Article: Search for B+ meson decay to a1+ K*0

  P. del Amo Sanchez, J.P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], B. Stugu, L. Sun, M. Battaglia, D.N. Brown, B. Hooberman, L.T. Kerth, Yu.G. Kolomensky, G. Lynch, I.L. Osipenkov, T. Tanabe
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  ABSTRACT: We present a search for the decay B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892). The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represent 465 million B{anti B} pairs produced in e{sup +}e{sup -} annihilation at the energy of the {Upsilon}(4S). We find no significant signal and set an upper limit at 90% confidence level on the product of branching fractions B(B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892)) x B({alpha}{sup +}{sub 1}(1260) --> {pi}{sup +}{pi}{sup -}{pi}{sup +}) of 1.8 x 10{sup -6}.
  Phys.Rev.D82:091101,2010. 08/2011; 82.
• Conference Proceeding: Evidence for B+ --> tau+ nu_tau Decays using Hadronic B Tags

  P. del Amo Sanchez, J.P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D.A. Milanes, A. Palano, [......], G. Eigen, B. Stugu, L. Sun, D.N. Brown, L.T. Kerth, Yu.G. Kolomensky, G. Lynch, I.L. Osipenkov, H. Koch, T. Schroeder
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  ABSTRACT: We present a search for the decay B{sup +} --> {tau}{sup +} {nu}{sub {tau}} using 467.8 x 10{sup 6} B{anti B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with on completely reconstructed B{sup -} in an hadronic decay mode (B{sup -} --> D{sup (*)0}X{sup -} and B{sup -} --> J/{psi} X{sup -}). We examine the rest of the event to search for a B{sup +} --> {tau}{sup +} {nu}{sub {tau}} decay. We identify the {tau}{sup +} lepton in the following modes: {tau}{sup +} --> e{sup +} {nu}{sub e}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {mu}{sup +} {nu}{sub {mu}}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {pi}{sup +}{anti {nu}}{sub {tau}} and {tau}{sup +} --> {rho}{anti {nu}}{sub {tau}}. We find an excess of events with respect to expected background, which excludes the null signal hypothesis at the level of 3.3 {sigma} and can be converted to a branching fraction central value of B(B{sup +} --> {tau}{sup +} {nu}{sub {tau}})= (1.80{sup + 0.57}{sub - 0.54}(stat.) {+-} 0.26 (syst.)) x 10{sup -4}.
  08/2011
• Article: Observation of the decay B- → D(s)((*)+) K- ℓ- ν(ℓ).

  P del Amo Sanchez, J P Lees, V Poireau, E Prencipe, V Tisserand, J Garra Tico, E Grauges, M Martinelli, A Palano, M Pappagallo, [......], P F Harrison, T E Latham, E M T Puccio, H R Band, S Dasu, K T Flood, Y Pan, R Prepost, C O Vuosalo, S L Wu
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  ABSTRACT: We report the observation of the decay B- → D(s)((*)+) K- ℓ- ν(ℓ) based on 342  fb(-1) of data collected at the Υ(4S) resonance with the BABAR detector at the PEP-II e+ e- storage rings at SLAC. A simultaneous fit to three D(s)(+) decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B- → D(s)((*)+) K- ℓ- ν(ℓ) with a significance greater than 5 standard deviations (including systematic uncertainties) and measure its branching fraction to be B(B- → D(s)((*)+) K- ℓ- ν(ℓ)) = [6.13(-1.03)(+1.04)(stat)±0.43(syst)±0.51(B(D(s)))]×10(-4), where the last error reflects the limited knowledge of the D(s) branching fractions.
  Physical Review Letters 07/2011; 107(4):041804. · 7.37 Impact Factor
• Article: Observation of ηc(1S) and ηc(2S) decays to K+K-π+π-π0 in two-photon interactions

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We study the processes γγ→KS0K±π∓ and γγ→K+K-π+π-π0 using a data sample of 519.2fb-1 recorded by the BABAR detector at the PEP-II asymmetric-energy e+e- collider at center-of-mass energies near the Υ(nS) (n=2, 3, 4) resonances. We observe the ηc(1S), χc0(1P) and ηc(2S) resonances produced in two-photon interactions and decaying to K+K-π+π-π0, with significances of 18.1, 5.4 and 5.3 standard deviations (including systematic errors), respectively, and report 4.0σ evidence of the χc2(1P) decay to this final state. We measure the ηc(2S) mass and width in KS0K±π∓ decays, and obtain the values m(ηc(2S))=3638.5±1.5±0.8 MeV/c2 and Γ(ηc(2S))=13.4±4.6±3.2 MeV, where the first uncertainty is statistical and the second is systematic. We measure the two-photon width times branching fraction for the reported resonance signals, and search for the χc2(2P) resonance, but no significant signal is observed.
  Phys. Rev. D. 07/2011; 84(1).
• Article: Search for production of invisible final states in single-photon decays of Υ(1S).

  P del Amo Sanchez, J P Lees, V Poireau, E Prencipe, V Tisserand, J Garra Tico, E Grauges, M Martinelli, D A Milanes, A Palano, [......], P F Harrison, T E Latham, E M T Puccio, H R Band, S Dasu, K T Flood, Y Pan, R Prepost, C O Vuosalo, S L Wu
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  ABSTRACT: We search for single-photon decays of the Υ(1S) resonance, Υ → γ + invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A⁰, or a pair of dark matter particles, χχ. Both A⁰ and χ are assumed to have zero spin. We tag Υ(1S) decays with a dipion transition Υ(2S) → π⁺π⁻Υ(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m(A⁰) ≤ 9.2 GeV and m(χ) ≤ 4.5 GeV in the sample of 98 × 10⁶ Υ(2S) decays collected with the BABAR detector and set stringent limits on new physics models that contain light dark matter states.
  Physical Review Letters 07/2011; 107(2):021804. · 7.37 Impact Factor
• Article: Searches for the baryon- and lepton-number violating decays $B^0\rightarrow\Lambda_c^ \ell^-$, $B^-\rightarrow\Lambda\ell^-$, and $B^-\rightarrow\bar{\Lambda}\ell^-$

  P. del Amo Sanchez, J.P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D.A. Milanes, A. Palano, [......], G. Eigen, B. Stugu, L. Sun, D.N. Brown, L.T. Kerth, Yu.G. Kolomensky, G. Lynch, I.L. Osipenkov, H. Koch, T. Schroeder
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  ABSTRACT: Searches for B mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either {Lambda}{sub c} or {Lambda} and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range (3.2 - 520) x 10{sup -8} are set on the branching fractions at the 90% confidence level.
  Phys.Rev.D83:091101,2011. 06/2011;
• Article: Analysis of the D+→K-π+e+νe decay channel

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D. A. Milanes, A. Palano, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: Using 347.5 fb-1 of data recorded by the BABAR detector at the PEP-II electron-positron collider, 244×103 signal events for the D+→K-π+e+νe decay channel are analyzed. This decay mode is dominated by the K̅ *(892)0 contribution. We determine the K̅ *(892)0 parameters: mK*(892)0=(895.4±0.2±0.2) MeV/c2, ΓK*(892)00=(46.5±0.3±0.2) MeV/c2, and the Blatt-Weisskopf parameter rBW=2.1±0.5±0.5 (GeV/c)-1, where the first uncertainty comes from statistics and the second from systematic uncertainties. We also measure the parameters defining the corresponding hadronic form factors at q2=0 (rV=V(0)/A1(0)=1.463±0.017±0.031, r2=A2(0)/A1(0)=0.801±0.020±0.020) and the value of the axial-vector pole mass parametrizing the q2 variation of A1 and A2: mA=(2.63±0.10±0.13) GeV/c2. The S-wave fraction is equal to (5.79±0.16±0.15)%. Other signal components correspond to fractions below 1%. Using the D+→K-π+π+ channel as a normalization, we measure the D+ semileptonic branching fraction: B(D+→K-π+e+νe)=(4.00±0.03±0.04±0.09)×10-2, where the third uncertainty comes from external inputs. We then obtain the value of the hadronic form factor A1 at q2=0: A1(0)=0.6200±0.0056±0.0065±0.0071. Fixing the P-wave parameters, we measure the phase of the S wave for several values of the Kπ mass. These results confirm those obtained with Kπ production at small momentum transfer in fixed target experiments.
  Phys. Rev. D. 03/2011; 83(7).
• Article: Measurement of the B0→π-ℓ+ν and B+→η(′)ℓ+ν branching fractions, the B0→π-ℓ+ν and B+→ηℓ+ν form-factor shapes, and determination of |Vub|

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D. A. Milanes, A. Palano, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We report the results of a study of the exclusive charmless semileptonic decays, B+→η(′)ℓ+ν and B0→π-ℓ+ν, undertaken with approximately 464×106 BB̅ pairs collected at the Υ(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B+→ηℓ+ν and B0→π-ℓ+ν decays in three and 12 bins of q2, respectively, from which we extract the f+(q2) form-factor shapes and the total branching fractions B(B+→ηℓ+ν)=(0.36±0.05stat±0.04syst)×10-4 and B(B0→π-ℓ+ν)=(1.42±0.05stat±0.07syst)×10-4. We also measure B(B+→η′ℓ+ν)=(0.24±0.08stat±0.03syst)×10-4. We obtain values for the magnitude of the CKM matrix element |Vub| using three different QCD calculations.
  Phys. Rev. D. 03/2011; 83(5).
• Article: Measurement of the B0→π-ℓ+ν and B+→η(')ℓ+ν branching fractions, the B0→π-ℓ+ν and B+→ηℓ+ν form-factor shapes, and determination of |Vub|

  P. Del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D. A. Milanes, A. Palano, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We report the results of a study of the exclusive charmless semileptonic decays, B+→η(')ℓ+ν and B0→π-ℓ+ν, undertaken with approximately 464×106 BB¯ pairs collected at the Υ(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B+→ηℓ+ν and B0→π-ℓ+ν decays in three and 12 bins of q2, respectively, from which we extract the f+(q2) form-factor shapes and the total branching fractions B(B+→ηℓ+ν)=(0.36±0.05stat±0.04syst)×10-4 and B(B0→π-ℓ+ν)=(1.42±0.05stat±0.07syst)×10-4. We also measure B(B+→η'ℓ+ν)=(0.24±0.08stat±0.03syst)×10-4. We obtain values for the magnitude of the CKM matrix element |Vub| using three different QCD calculations.
  Physical review D: Particles and fields 02/2011; 83(5):52011.
• Article: Measurements of branching fractions, polarizations, and direct CP-violation asymmetries in B+→ρ0K*+ and B+→f0(980)K*+ decays

  P. Del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D. A. Milanes, A. Palano, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We present measurements of the branching fractions, longitudinal polarization, and direct CP-violation asymmetries for the decays B+→ρ0K*+ and B+→f0(980)K*+ with a sample of (467±5)×106BB¯ pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory. We observe B+→ρ0K*+ with a significance of 5.3σ and measure the branching fraction B(B+→ρ0K*+)=(4.6±1.0±0.4)×10-6, the longitudinal polarization fL=0.78±0.12±0.03, and the CP-violation asymmetry ACP=0.31±0.13±0.03. We observe B+→f0(980)K*+ and measure the branching fraction B(B+→f0(980)K*+)×B(f0(980)→π+π-)=(4.2±0.6±0.3)×10-6 and the CP-violation asymmetry ACP=-0.15±0.12±0.03. The first uncertainty quoted is statistical and the second is systematic.
  Physical review D: Particles and fields 02/2011; 83(5):51101.
• Article: Measurement of the B0→π-ℓ+ν and B+→η(')ℓ+ν branching fractions, the B0→π-ℓ+ν and B+→ηℓ+ν form-factor shapes, and determination of |Vub|

  P. Del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, D. A. Milanes, A. Palano, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We report the results of a study of the exclusive charmless semileptonic decays, B+→η(')ℓ+ν and B0→π-ℓ+ν, undertaken with approximately 464×106 BB¯ pairs collected at the Υ(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B+→ηℓ+ν and B0→π-ℓ+ν decays in three and 12 bins of q2, respectively, from which we extract the f+(q2) form-factor shapes and the total branching fractions B(B+→ηℓ+ν)=(0.36±0.05stat±0.04syst)×10-4 and B(B0→π-ℓ+ν)=(1.42±0.05stat±0.07syst)×10-4. We also measure B(B+→η'ℓ+ν)=(0.24±0.08stat±0.03syst)×10-4. We obtain values for the magnitude of the CKM matrix element |Vub| using three different QCD calculations.
  Physical review D: Particles and fields 02/2011; 83(5):52011.
• Article: Study of B→πlν and B→ρlν decays and determination of |Vub|

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], 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
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  ABSTRACT: We present an analysis of exclusive charmless semileptonic B-meson decays based on 377×106 BB̅ pairs recorded with the BABAR detector at the Υ(4S) resonance. We select four event samples corresponding to the decay modes B0→π-ℓ+ν, B+→π0ℓ+ν, B0→ρ-ℓ+ν, and B+→ρ0ℓ+ν and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two B→πℓν samples, and similarly the two B→ρℓν samples, and measure the branching fractions B(B0→π-ℓ+ν)=(1.41±0.05±0.07)×10-4 and B(B0→ρ-ℓ+ν)=(1.75±0.15±0.27)×10-4, where the errors are statistical and systematic. We compare the measured distribution in q2, the momentum transfer squared, with predictions for the form factors from QCD calculations and determine the Cabibbo-Kobayashi-Maskawa matrix element |Vub|. Based on the measured partial branching fraction for B→πℓν in the range q2<12 GeV2 and the most recent QCD light-cone sum-rule calculations, we obtain |Vub|=(3.78±0.13-0.40+0.55)×10-3, where the errors refer to the experimental and theoretical uncertainties. From a simultaneous fit to the data over the full q2 range and the FNAL/MILC lattice QCD results, we obtain |Vub|=(2.95±0.31)×10-3 from B→πℓν, where the error is the combined experimental and theoretical uncertainty.
  Phys. Rev. D. 02/2011; 83(3).
• Article: Search for the decay B0→γγ

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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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.
  Phys. Rev. D. 02/2011; 83(3).
• Article: Studies of τ-→ηK-ντ and τ-→ηπ-ντ at BABAR and a search for a second-class current

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We report on analyses of tau lepton decays τ-→ηK-ντ and τ-→ηπ-ντ, with η→π+π-π0, using 470 fb-1 of data from the BABAR experiment at PEP-II, collected at center-of-mass energies at and near the Υ(4S) resonance. We measure the branching fraction for the τ-→ηK-ντ decay mode, B(τ-→ηK-ντ)=(1.42±0.11(stat)±0.07(syst))×10-4, and report a 95% confidence level upper limit for the second-class current process τ-→ηπ-ντ, B(τ-→ηπ-ντ)<9.9×10-5.
  Phys. Rev. D. 02/2011; 83(3).
• Article: Search for the rare decay B→Kνν̅

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], P. F. Harrison, T. E. Latham, E. M. T. Puccio, H. R. Band, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We present a search for the rare decays B+→K+νν̅ and B0→K0νν̅ using 459×106 BB̅ pairs collected with the BABAR detector at the SLAC National Accelerator Laboratory. Flavor-changing neutral-current decays such as these are forbidden at tree level but can occur through one-loop diagrams in the standard model (SM), with possible contributions from new physics at the same order. The presence of two neutrinos in the final state makes identification of signal events challenging, so reconstruction in the semileptonic decay channels B→D(*)lν of the B meson recoiling from the signal B is used to suppress backgrounds. We set an upper limit at the 90% confidence level (CL) of 1.3×10-5 on the total branching fraction for B+→K+νν̅ , and 5.6×10-5 for B0→K0νν̅ . We additionally report 90% CL upper limits on partial branching fractions in two ranges of dineutrino mass squared for B+→K+νν̅ .
  Phys. Rev. D. 12/2010; 82(11).
• Article: Search for B+→D+K0 and B+→D+K*0 decays

  P. del Amo Sanchez, J. P. Lees, V. Poireau, E. Prencipe, V. Tisserand, J. Garra Tico, E. Grauges, M. Martinelli, A. Palano, M. Pappagallo, [......], T. E. Latham, E. M. T. Puccio, H. R. Band, X. Chen, S. Dasu, K. T. Flood, Y. Pan, R. Prepost, C. O. Vuosalo, S. L. Wu
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  ABSTRACT: We report a search for the rare decays B+→D+K0 and B+→D+K*0 in an event sample of approximately 465×106 BB̅ pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC National Accelerator Laboratory. We find no significant evidence for either mode and we set 90% probability upper limits on the branching fractions of B(B+→D+K0)<2.9×10-6 and B(B+→D+K*0)<3.0×10-6.
  Phys. Rev. D. 11/2010; 82(9).