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

Abstract

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 the KEKB e{sup +}e{sup -} collider.

Authors:
; ; ; ; ; ;  [1]; ;  [2];  [3]; ; ; ; ; ; ; ; ; ; more »;  [4] « less
  1. J. Stefan Institute, Ljubljana (Slovenia)
  2. University of Ljubljana, Ljubljana (Slovenia)
  3. (Slovenia)
  4. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan) (and others)
Publication Date:
OSTI Identifier:
20951391
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 21; Other Information: DOI: 10.1103/PhysRevLett.98.211803; (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; CP INVARIANCE; D NEUTRAL MESONS; EIGENSTATES; KAONS MINUS; KAONS PLUS; LIFETIME; PAIR PRODUCTION; PARTICLE DECAY; PIONS MINUS; PIONS PLUS

Citation Formats

Staric, M., Bitenc, U., Bizjak, I., Fratina, S., Gorisek, A., Pestotnik, R., Zupanc, A., Golob, B., Krizan, P., J. Stefan Institute, Ljubljana, Abe, K., Adachi, I., Dragic, J., Haba, J., Hazumi, M., Higuchi, T., Itoh, R., Iwasaki, Y., Katayama, N., Kichimi, H., and Krokovny, P.. Evidence for D{sup 0}-D{sup 0} Mixing. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.211803.
Staric, M., Bitenc, U., Bizjak, I., Fratina, S., Gorisek, A., Pestotnik, R., Zupanc, A., Golob, B., Krizan, P., J. Stefan Institute, Ljubljana, Abe, K., Adachi, I., Dragic, J., Haba, J., Hazumi, M., Higuchi, T., Itoh, R., Iwasaki, Y., Katayama, N., Kichimi, H., & Krokovny, P.. Evidence for D{sup 0}-D{sup 0} Mixing. United States. doi:10.1103/PHYSREVLETT.98.211803.
Staric, M., Bitenc, U., Bizjak, I., Fratina, S., Gorisek, A., Pestotnik, R., Zupanc, A., Golob, B., Krizan, P., J. Stefan Institute, Ljubljana, Abe, K., Adachi, I., Dragic, J., Haba, J., Hazumi, M., Higuchi, T., Itoh, R., Iwasaki, Y., Katayama, N., Kichimi, H., and Krokovny, P.. Fri . "Evidence for D{sup 0}-D{sup 0} Mixing". United States. doi:10.1103/PHYSREVLETT.98.211803.
@article{osti_20951391,
title = {Evidence for D{sup 0}-D{sup 0} Mixing},
author = {Staric, M. and Bitenc, U. and Bizjak, I. and Fratina, S. and Gorisek, A. and Pestotnik, R. and Zupanc, A. and Golob, B. and Krizan, P. and J. Stefan Institute, Ljubljana and Abe, K. and Adachi, I. and Dragic, J. and Haba, J. and Hazumi, M. and Higuchi, T. and Itoh, R. and Iwasaki, Y. and Katayama, N. and Kichimi, H. and Krokovny, P.},
abstractNote = {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 the KEKB e{sup +}e{sup -} collider.},
doi = {10.1103/PHYSREVLETT.98.211803},
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 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.
  • 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.