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Title: Search for D^0-\overline{D}^0 Mixing Using Doubly Flavor TaggedSemileptonic Decay Modes

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
903300
Report Number(s):
SLAC-PUB-12494
Journal ID: ISSN 0556-2821; PRVDAQ; arXiv:0705.0704; TRN: US0703519
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review D
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DECAY; PIONS; PRODUCTION; SEMILEPTONIC DECAY; SIMULATION; FLAVOR; Experiment-HEP,HEPEX

Citation Formats

Aubert, B. Search for D^0-\overline{D}^0 Mixing Using Doubly Flavor TaggedSemileptonic Decay Modes. United States: N. p., 2007. Web. doi:10.1103/PhysRevD.76.014018.
Aubert, B. Search for D^0-\overline{D}^0 Mixing Using Doubly Flavor TaggedSemileptonic Decay Modes. United States. doi:10.1103/PhysRevD.76.014018.
Aubert, B. Fri . "Search for D^0-\overline{D}^0 Mixing Using Doubly Flavor TaggedSemileptonic Decay Modes". United States. doi:10.1103/PhysRevD.76.014018. https://www.osti.gov/servlets/purl/903300.
@article{osti_903300,
title = {Search for D^0-\overline{D}^0 Mixing Using Doubly Flavor TaggedSemileptonic Decay Modes},
author = {Aubert, B.},
abstractNote = {},
doi = {10.1103/PhysRevD.76.014018},
journal = {Physical Review D},
number = ,
volume = ,
place = {United States},
year = {Fri May 11 00:00:00 EDT 2007},
month = {Fri May 11 00:00:00 EDT 2007}
}
  • Based on an 87-fb{sup -1} data set collected by the BABAR detector at the PEP-II asymmetric-energy B Factory, a search for D{sup 0}-D-bar{sup 0} mixing has been made using the semileptonic decay modes D*{sup +}{yields}{pi}{sup +}D{sup 0}, D{sup 0}{yields}K{sup (}*{sup )}e{nu} (+c.c.). The use of these modes allows unambiguous flavor tagging and a combined fit of the D{sup 0} decay time and D*{sup +}-D{sup 0} mass difference ({delta}M) distributions. The high-statistics sample of unmixed semileptonic D{sup 0} decays is used to model the {delta}M distribution and time dependence of mixed events directly from the data. Neural networks are used tomore » select events and reconstruct the D{sup 0}. A result consistent with no charm mixing has been obtained, R{sub mix}=0.0023{+-}0.0012{+-}0.0004. This corresponds to an upper limit of R{sub mix}<0.0042 (90% C.L.)« less
  • 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 measuremore » 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.« less
  • The authors present a measurement of D{sup 0}-{bar D}{sup 0} mixing parameters using the ratios of lifetimes extracted from a sample of D{sup 0} mesons produced through the process D*{sup +} {yields} D{sup 0}{pi}{sup +}, that decay to K{sup -}{pi}{sup +}, I{sup -}K{sup +}, or {pi}{sup -}{pi}{sup +}. the Cabibbo-suppressed modes K{sup -}K{sup +} and {pi}{sup -}{pi}{sup +} are compared to the Cabibbo-favored mode K{sup -}{pi}{sup +} to obtain a measurement of ycp, which in the limit of CP conservation corresponds to the mixing parameter y. The analysis is based on a data sample of 384 fb{sup -1} collected bymore » the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider. They obtain ycp = [1.24 {+-} 0.39(stat) {+-} 0.13(syst)]%, which is evidence of D{sup 0}-{bar D}{sup 0} mixing at the 3{sigma} level, and {Delta}Y = [-0.26 {+-} 0.36(stat) {+-} 0.08(syst)]%, where {Delta}Y constrains possible CP violation. Combining this result with a previous BABAR measurement of ycp obtained from a separate sample of D{sup 0} {yields} K{sup -}K{sup +} events, they obtain ycp = [1.03 {+-} 0.33(stat) {+-} 0.19(syst)]%.« less
  • We report the result of a search for {ital D}{sup 0}{ital {bar D}}{sup 0} mixing in the data from hadroproduction experiment E791 at Fermilab. We use the charge of the pion from the strong decay {ital D}{sup {asterisk}+}{r_arrow}{ital D}{sup 0}{pi}{sup +} (and charge conjugate) to identify the charm quantum number of the neutral {ital D} at production, and the charge of the lepton and the kaon in the semileptonic decays {ital D}{sup 0}{r_arrow}{ital Ke}{nu} and {ital K}{mu}{nu} to identify the charm at the time of decay. No evidence of mixing is seen. We set a 90{percent} confidence level upper limitmore » on mixing of {ital r}{lt}0.50{percent}, where {ital r}={Gamma}({ital D}{sup 0}{r_arrow}{bar {ital D}}{sup 0}{r_arrow}{ital K}{sup +}{ital l}{sup {minus}}{nu}{sub {ital l}})/{Gamma}({ital D}{sup 0}{r_arrow}{ital K}{sup {minus}}{ital l}{sup +}{nu}{sub {ital l}}). {copyright} {ital 1996 The American Physical Society.}« less
  • We present results of a search for D{sup 0}-{bar D}{sup 0} mixing and doubly-Cabibbo-suppressed decays of the D{sup 0} in Fermilab experiment E791, a fixed-target charm hadroproduction experiment. We look for evidence of mixing in the decay chain D{sup {asterisk}}{r_arrow}{pi}D{r_arrow}{pi}(K{pi} or K{pi}{pi}{pi}). If the charge of the pion from the D{sup {asterisk}} decay is the same as the charge of the kaon from the D decay (a {open_quotes}wrong-sign{close_quotes} event), mixing may have occurred. Mixing can be distinguished from other sources of wrong-sign events (such as doubly-Cabibbo-suppressed decays) by analyzing the distribution of decay times. We see no evidence of mixing.more » Allowing for CP violation in the interference between DCS and mixing amplitudes our fitted ratio for mixed to unmixed decay rates is r{sub mix}=(0.39{sub {minus}0.32}{sup +0.36}{plus_minus}0.16){percent}. This corresponds to a 90{percent} C.L. upper limit of r{sub mix}{lt}0.85{percent}. The sensitivity of this result is comparable to that of previous measurements, but the assumptions made in fitting the data are notably more general. We present results from many fits to our data under various assumptions. If we assume r{sub mix}=0, we find a two-sigma wrong-sign enhancement in the K{pi} mode which we ascribe to doubly Cabibbo-suppressed decays. The ratios of doubly Cabibbo-suppressed decays to Cabibbo-favored decays are r{sub dcs}(K{pi})=(0.68{sub {minus}0.33}{sup +0.34}{plus_minus}0.07){percent} and r{sub dcs}(K{pi}{pi}{pi})=(0.25{sub {minus}0.34}{sup +0.36}{plus_minus}0.03){percent}. {copyright} {ital 1997} {ital The American Physical Society}« less