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Title: Evidence for D{sup 0}-D{sup 0} Mixing

Abstract

We present evidence for D{sup 0}-D{sup 0} mixing in D{sup 0}{yields}K{sup +}{pi}{sup -} decays from 384 fb{sup -1} of e{sup +}e{sup -} colliding-beam data recorded near {radical}(s)=10.6 GeV with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center. We find the mixing parameters x{sup '2}=[-0.22{+-}0.30(stat){+-}0.21(syst)]x10{sup -3} and y{sup '}=[9.7{+-}4.4(stat){+-}3.1(syst)]x10{sup -3} and a correlation between them of -0.95. This result is inconsistent with the no-mixing hypothesis with a significance of 3.9 standard deviations. We measure R{sub D}, the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates, to be [0.303{+-}0.016(stat){+-}0.010(syst)]%. We find no evidence for CP violation.

Authors:
; ; ; ; ; ; ; ;  [1]; ;  [2]; ;  [3]; ; ;  [4]; ; ; ;  [5]
  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. University of Bergen, Institute of Physics, N-5007 Bergen (Norway)
  5. Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720 (United States) (and others)
Publication Date:
OSTI Identifier:
20951390
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 21; Other Information: DOI: 10.1103/PhysRevLett.98.211802; (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; COLLIDING BEAMS; CP INVARIANCE; D NEUTRAL MESONS; ELECTRON BEAMS; GEV RANGE 10-100; KAONS PLUS; MIXING; PARTICLE DECAY; PIONS MINUS; POSITRON BEAMS; STANFORD LINEAR ACCELERATOR CENTER; STORAGE RINGS

Citation Formats

Aubert, B., Bona, M., Boutigny, D., Karyotakis, Y., Lees, J. P., Poireau, V., Prudent, X., Tisserand, V., Zghiche, A., Garra Tico, J., Grauges, E., Lopez, L., Palano, A., Eigen, G., Stugu, B., Sun, L., Abrams, G. S., Battaglia, M., Brown, D. N., and Button-Shafer, J.. Evidence for D{sup 0}-D{sup 0} Mixing. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.211802.
Aubert, B., Bona, M., Boutigny, D., Karyotakis, Y., Lees, J. P., Poireau, V., Prudent, X., Tisserand, V., Zghiche, A., Garra Tico, J., Grauges, E., Lopez, L., Palano, A., Eigen, G., Stugu, B., Sun, L., Abrams, G. S., Battaglia, M., Brown, D. N., & Button-Shafer, J.. Evidence for D{sup 0}-D{sup 0} Mixing. United States. doi:10.1103/PHYSREVLETT.98.211802.
Aubert, B., Bona, M., Boutigny, D., Karyotakis, Y., Lees, J. P., Poireau, V., Prudent, X., Tisserand, V., Zghiche, A., Garra Tico, J., Grauges, E., Lopez, L., Palano, A., Eigen, G., Stugu, B., Sun, L., Abrams, G. S., Battaglia, M., Brown, D. N., and Button-Shafer, J.. Fri . "Evidence for D{sup 0}-D{sup 0} Mixing". United States. doi:10.1103/PHYSREVLETT.98.211802.
@article{osti_20951390,
title = {Evidence for D{sup 0}-D{sup 0} Mixing},
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 Garra Tico, J. and Grauges, E. and Lopez, L. and Palano, A. and Eigen, G. and Stugu, B. and Sun, L. and Abrams, G. S. and Battaglia, M. and Brown, D. N. and Button-Shafer, J.},
abstractNote = {We present evidence for D{sup 0}-D{sup 0} mixing in D{sup 0}{yields}K{sup +}{pi}{sup -} decays from 384 fb{sup -1} of e{sup +}e{sup -} colliding-beam data recorded near {radical}(s)=10.6 GeV with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center. We find the mixing parameters x{sup '2}=[-0.22{+-}0.30(stat){+-}0.21(syst)]x10{sup -3} and y{sup '}=[9.7{+-}4.4(stat){+-}3.1(syst)]x10{sup -3} and a correlation between them of -0.95. This result is inconsistent with the no-mixing hypothesis with a significance of 3.9 standard deviations. We measure R{sub D}, the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates, to be [0.303{+-}0.016(stat){+-}0.010(syst)]%. We find no evidence for CP violation.},
doi = {10.1103/PHYSREVLETT.98.211802},
journal = {Physical Review Letters},
number = 21,
volume = 98,
place = {United States},
year = {Fri May 25 00:00:00 EDT 2007},
month = {Fri May 25 00:00:00 EDT 2007}
}
  • We observe evidence for D{sup 0}-D{sup 0} mixing by measuring the difference in the apparent lifetime when a D{sup 0} meson decays to the CP eigenstates K{sup +}K{sup -} and {pi}{sup +}{pi}{sup -} and when it decays to the final state K{sup -}{pi}{sup +}. We find the relative difference of the lifetimes y{sub CP} to be [1.31{+-}0.32(stat){+-}0.25(syst)]%, 3.2 standard deviations from zero. We also search for a CP asymmetry between D{sup 0} and D{sup 0} decays; no evidence for CP violation is found. These results are based on 540 fb{sup -1} of data recorded by the Belle detector at themore » KEKB e{sup +}e{sup -} collider.« less
  • We measure the time dependence of the ratio of decay rates for the rare decay D{sup 0}{yields}K{sup +}{pi}{sup -} to the Cabibbo-favored decay D{sup 0}{yields}K{sup -}{pi}{sup +}. A signal of 12.7x10{sup 3} D{sup 0}{yields}K{sup +}{pi}{sup -} decays was obtained using the Collider Detector at Fermilab II detector at the Fermilab Tevatron with an integrated luminosity of 1.5 fb{sup -1}. We measure the D{sup 0}-D{sup 0} mixing parameters (R{sub D},y{sup '},x{sup '2}), and find that the data are inconsistent with the no-mixing hypothesis with a probability equivalent to 3.8 Gaussian standard deviations.
  • We report a direct measurement of D{sup 0}-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)]x10{sup -3}, and y=[5.7{+-}2.0(stat){+-}1.3(syst){+-}0.7(model)]x10{sup -3}. Thesemore » 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.« less
  • The authors present a search for D{sup 0}-{bar D}{sup 0} mixing using regions of phase space in which the rate of doubly Cabibbo-suppressed decays D{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0} relative to Cabibbo-favored decays D{sup 0} {yields} K{sup -} {pi}{sup +}{pi}{sup 0} is reduced. They analyze 230.4 fb{sup -1} of data collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. They present results with and without the assumption of CP conservation. Assuming CP conservation, they measure the time-integrated mixing rate R{sub M} = (0.023{sub -0.014}{sup +0.018}(stat.) {+-} 0.004(syst.))%, and R{sub M} < 0.054% atmore » the 95% confidence level. They find that the data are consistent with no mixing at the 4.5% confidence level. Considering the entire allowed phase space, they measure the branching ratio for D{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0} relative to D{sup 0} {yields} K{sup -} {pi}{sup +}{pi}{sup 0} to be (0.214 {+-} 0.008(stat.) {+-} 0.008(syst.))%.« less
  • We report evidence for B{sup 0}{yields}D{sup +}D{sup -} and the first observation of the decay modes B{sup -}{yields}D{sup 0}D{sup -} and B{sup -}{yields}D{sup 0}D{sup *-} based on a sample of 152x10{sup 6} BB events collected by the Belle detector at KEKB. The branching fractions for B{sup 0}{yields}D{sup +}D{sup -}, B{sup -}{yields}D{sup 0}D{sup -}, and B{sup -}{yields}D{sup 0}D{sup *-} are found to be (1.91{+-}0.51{+-}0.30)x10{sup -4} (4.83{+-}0.78{+-}0.58)x10{sup -4}, and (4.57{+-}0.71{+-}0.56)x10{sup -4}, respectively. Charge asymmetries in the B{sup -}{yields}D{sup 0}D{sup -} and B{sup -}{yields}D{sup 0}D{sup *-} channels are consistent with zero.