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Title: Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}

Abstract

We search for the decays B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0}, B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980), and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) in a sample of about 384x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at Stanford Linear Accelerator Center. We find evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} with 3.5{sigma} significance and measure the branching fraction B=(1.07{+-}0.33{+-}0.19)x10{sup -6} and longitudinal polarization fraction f{sub L}=0.87{+-}0.13{+-}0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the Cabibbo-Kobayashi-Maskawa quark-mixing matrix unitarity angle {alpha} due to penguin contributions in B{yields}{rho}{rho} decays is 18 deg. at the 1{sigma} level. We also set upper limits on the B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980) and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) decay rates.

Authors:
; ; ; ; ; ; ; ;  [1];  [2];  [3]; ; ; ; ;  [4]; ; ;  [5];  [6]
  1. Laboratoire de Physique des Particules, IN2P3/CNRS et Universite de Savoie, F-74941 Annecy-Le-Vieux (France)
  2. Universitat de Barcelona, Facultat de Fisica, Departament ECM, E-08028 Barcelona (Spain)
  3. Universita di Bari, Dipartimento di Fisica and INFN, I-70126 Bari (Italy)
  4. Institute of High Energy Physics, Beijing 100039 (China)
  5. University of Bergen, Institute of Physics, N-5007 Bergen (Norway)
  6. Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720 (United States) (and others)
Publication Date:
OSTI Identifier:
20957745
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevLett.98.111801; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; B NEUTRAL MESONS; BRANCHING RATIO; CABIBBO ANGLE; F0-980 MESONS; KOBAYASHI-MASKAWA MATRIX; PAIR PRODUCTION; PARTICLE DECAY; POLARIZATION; QUARKS; RHO-770 MESONS; STANFORD LINEAR ACCELERATOR CENTER; UNITARITY

Citation Formats

Aubert, B., Bona, M., Boutigny, D., Karyotakis, Y., Lees, J. P., Poireau, V., Prudent, X., Tisserand, V., Zghiche, A., Grauges, E., Palano, A., Chen, J. C., Qi, N. D., Rong, G., Wang, P., Zhu, Y. S., Eigen, G., Ofte, I., Stugu, B., and Abrams, G. S.. Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.111801.
Aubert, B., Bona, M., Boutigny, D., Karyotakis, Y., Lees, J. P., Poireau, V., Prudent, X., Tisserand, V., Zghiche, A., Grauges, E., Palano, A., Chen, J. C., Qi, N. D., Rong, G., Wang, P., Zhu, Y. S., Eigen, G., Ofte, I., Stugu, B., & Abrams, G. S.. Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}. United States. doi:10.1103/PHYSREVLETT.98.111801.
Aubert, B., Bona, M., Boutigny, D., Karyotakis, Y., Lees, J. P., Poireau, V., Prudent, X., Tisserand, V., Zghiche, A., Grauges, E., Palano, A., Chen, J. C., Qi, N. D., Rong, G., Wang, P., Zhu, Y. S., Eigen, G., Ofte, I., Stugu, B., and Abrams, G. S.. Fri . "Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}". United States. doi:10.1103/PHYSREVLETT.98.111801.
@article{osti_20957745,
title = {Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}},
author = {Aubert, B. and Bona, M. and Boutigny, D. and Karyotakis, Y. and Lees, J. P. and Poireau, V. and Prudent, X. and Tisserand, V. and Zghiche, A. and Grauges, E. and Palano, A. and Chen, J. C. and Qi, N. D. and Rong, G. and Wang, P. and Zhu, Y. S. and Eigen, G. and Ofte, I. and Stugu, B. and Abrams, G. S.},
abstractNote = {We search for the decays B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0}, B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980), and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) in a sample of about 384x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at Stanford Linear Accelerator Center. We find evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} with 3.5{sigma} significance and measure the branching fraction B=(1.07{+-}0.33{+-}0.19)x10{sup -6} and longitudinal polarization fraction f{sub L}=0.87{+-}0.13{+-}0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the Cabibbo-Kobayashi-Maskawa quark-mixing matrix unitarity angle {alpha} due to penguin contributions in B{yields}{rho}{rho} decays is 18 deg. at the 1{sigma} level. We also set upper limits on the B{sup 0}{yields}{rho}{sup 0}f{sub 0}(980) and B{sup 0}{yields}f{sub 0}(980)f{sub 0}(980) decay rates.},
doi = {10.1103/PHYSREVLETT.98.111801},
journal = {Physical Review Letters},
number = 11,
volume = 98,
place = {United States},
year = {Fri Mar 16 00:00:00 EDT 2007},
month = {Fri Mar 16 00:00:00 EDT 2007}
}
  • We present results from an analysis of B{sup 0}(B{sup 0}){yields}{rho}{sup +}{rho}{sup -} using 232x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We measure the longitudinal polarization fraction f{sub L}=0.978{+-}0.014(stat)(+0.021/-0.029)(syst) and the CP-violating parameters S{sub L}=-0.33{+-}0.24(stat)(+0.08/-0.14)(syst) and C{sub L}=-0.03{+-}0.18(stat){+-}0.09(syst). Using an isospin analysis of B{yields}{rho}{rho} decays, we determine the unitarity triangle parameter {alpha}. The solution compatible with the standard model is {alpha}=(100{+-}13) deg.
  • We have measured the branching fraction B, longitudinal polarization fraction f{sub L}, and CP asymmetry coefficients A and S for B{sup 0}{yields}{rho}{sup +}{rho}{sup -} decays with the Belle detector at the KEKB e{sup +}e{sup -} collider using 253 fb{sup -1} of data. We obtain B=[22.8{+-}3.8(stat){sub -2.6}{sup +2.3}(syst)]x10{sup -6}, f{sub L}=0.941{sub -0.040}{sup +0.034}(stat){+-}0.030(syst), A=0.00{+-}0.30(stat){+-}0.09(syst), and S=0.08{+-}0.41(stat){+-}0.09(syst). These values are used to constrain the Cabibbo-Kobayashi-Maskawa phase {phi}{sub 2}; the solution consistent with the standard model is {phi}{sub 2}=(88{+-}17) deg. or 59 deg. <{phi}{sub 2}<115 deg. at 90% C.L.
  • We report on a measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase {gamma} through a Dalitz analysis of neutral D decays to K{sub S}{sup 0}{pi}{sup -}{pi}{sup +} in the processes B{sup {+-}}{yields}D{sup (*)}K{sup {+-}}, D*{yields}D{pi}{sup 0}, D{gamma}. Using a sample of 227x10{sup 6} BB pairs collected by the BABAR detector, we measure the amplitude ratios r{sub B}=0.12{+-}0.08{+-}0.03{+-}0.04 and r{sub B}*=0.17{+-}0.10{+-}0.03{+-}0.03, the relative strong phases {delta}{sub B}=(104{+-}45{sub -21-24}{sup +17+16}) deg. and {delta}{sub B}*=(-64{+-}41{sub -12}{sup +14}{+-}15) deg. between the amplitudes A(B{sup -}{yields}D{sup (*)0}K{sup -}) and A(B{sup -}{yields}D{sup (*)0}K{sup -}), and {gamma}=(70{+-}31{sub -10-11}{sup +12+14}) deg. The first error is statistical, the second is the experimentalmore » systematic uncertainty, and the third reflects the Dalitz model uncertainty. The results for the strong and weak phases have a twofold ambiguity.« less
  • We present measurements of the branching fractions and charge asymmetries of B decays to all D{sup (*)}D{sup (*)} modes. Using 232x10{sup 6} BB pairs recorded on the {upsilon}(4S) resonance by the BABAR detector at the e{sup +}e{sup -} asymmetric B factory PEP-II at the Stanford Linear Accelerator Center, we measure the branching fractions B(B{sup 0}{yields}D*{sup +}D*{sup -})=(8.1{+-}0.6{+-}1.0)x10{sup -4}, B(B{sup 0}{yields}D*{sup {+-}}D{sup {+-}})=(5.7{+-}0.7{+-}0.7)x10{sup -4}, B(B{sup 0}{yields}D{sup +}D{sup -})=(2.8{+-}0.4{+-}0.5)x10{sup -4}, B(B{sup +}{yields}D*{sup +}D*{sup 0})=(8.1{+-}1.2{+-}1.2)x10{sup -4}, B(B{sup +}{yields}D*{sup +}D{sup 0})=(3.6{+-}0.5{+-}0.4)x10{sup -4}, B(B{sup +}{yields}D{sup +}D*{sup 0})=(6.3{+-}1.4{+-}1.0)x10{sup -4}, and B(B{sup +}{yields}D{sup +}D{sup 0})=(3.8{+-}0.6{+-}0.5)x10{sup -4}, where in each case the first uncertainty is statistical and themore » second systematic. We also determine the limits B(B{sup 0}{yields}D*{sup 0}D*{sup 0})<0.9x10{sup -4}, B(B{sup 0}{yields}D*{sup 0}D{sup 0})<2.9x10{sup -4}, and B(B{sup 0}{yields}D{sup 0}D{sup 0})<0.6x10{sup -4}, each at 90% confidence level. All decays above denote either member of a charge-conjugate pair. We also determine the CP-violating charge asymmetries A(B{sup 0}{yields}D*{sup {+-}}D{sup {+-}})=0.03{+-}0.10{+-}0.02, A(B{sup +}{yields}D*{sup +}D*{sup 0})=-0.15{+-}0.11{+-}0.02, A(B{sup +}{yields}D*{sup +}D{sup 0})=-0.06{+-}0.13{+-}0.02, A(B{sup +}{yields}D{sup +}D*{sup 0})=0.13{+-}0.18{+-}0.04, and A(B{sup +}{yields}D{sup +}D{sup 0})=-0.13{+-}0.14{+-}0.02. Additionally, when we combine these results with information from time-dependent CP asymmetries in B{sup 0}{yields}D{sup (*)+}D{sup (*)-} decays and world-averaged branching fractions of B decays to D{sub s}{sup (*}}D{sup (*)} modes, we find the Cabibbo-Kobayashi-Maskawa phase {gamma} is favored to lie in the range (0.07-2.77) radians (with a +0 or +{pi} radians ambiguity) at 68% confidence level.« less
  • We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle {gamma} through a Dalitz plot analysis of neutral D-meson decays to K{sub S}{sup 0}{pi}{sup +}{pi}{sup -} and K{sub S}{sup 0}K{sup +}K{sup -} produced in the processes B{sup {+-}}{yields}DK{sup {+-}}, B{sup {+-}}{yields}D*K{sup {+-}} with D*{yields}D{pi}{sup 0}, D{gamma}, and B{sup {+-}}{yields}DK*{sup {+-}} with K*{sup {+-}}{yields}K{sub S}{sup 0}{pi}{+-}, using 468 million BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. We measure {gamma}=(68{+-}14{+-}4{+-}3) deg. (modulo 180 deg.), where the first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the uncertaintymore » in the description of the neutral D decay amplitudes. This result is inconsistent with {gamma}=0 (no direct CP violation) with a significance of 3.5 standard deviations.« less