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Title: Measurement of D0-D0bar Mixing using the Ratio of D0->K-pi and K-K Lifetimes

Journal Article · · Phys.Rev.D80:071103,2009

We measure the rate of D{sup 0}-{bar D}{sup 0} mixing with the observable y{sub CP} = ({tau}{sub K{pi}}/{tau}{sub KK}) - 1, where {tau}{sub KK} and {tau}{sub K{pi}} are respectively the mean lifetimes of CP-even D{sup 0} {yields} K{sup +}K{sup -} and CP-mixed D{sup 0} {yields} K{sup -}{pi}{sup +} decays, using a data sample of 384 fb{sup -1} collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a sample of D{sup 0} and {bar D}{sup 0} decays where the initial flavor of the decaying meson is not determined, we obtain y{sub CP} = [1.12 {+-} 0.26(stat) {+-} 0.22(syst)]%, which excludes the no-mixing hypothesis at 3.3{sigma}, including both statistical and systematic uncertainties. This result is in good agreement with a previous BABAR measurement of y{sub CP} obtained from a sample of D*{sup +} {yields} D{sup 0}{pi}{sup +} events, where the D{sup 0} decays to K{sup -}{pi}{sup +}, K{sup +}K{sup -}, and {pi}{sup +}{pi}{sup -}, which is disjoint with the untagged D{sup 0} events used here. Combining the two results taking into account statistical and systematic uncertainties, where the systematic uncertainties are assumed to be 100% correlated, we find y{sub CP} = [1.16 {+-} 0.22(stat) {+-} 0.18(syst)]%, which excludes the no-mixing hypothesis at 4.1{sigma}.

Research Organization:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC02-76SF00515
OSTI ID:
968532
Report Number(s):
SLAC-PUB-13737; PRVDAQ; arXiv:0908.0761; TRN: US0904695
Journal Information:
Phys.Rev.D80:071103,2009, Vol. 80; ISSN 1550-7998
Country of Publication:
United States
Language:
English