skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Measurement of the lifetimes of the neutral and charged D mesons

Abstract

Results are presented on the use of a high-resolution drift chamber in the Mark II Detector at PEP to measure the lifetimes of D/sup 0/ and D/sup + -/ mesons produced in e/sup +/e/sup -/ annihilations at 29 GeV. Based on a sample of 74 events for the D/sup 0/ mesons and 23 events for the D/sup + -/ mesons, the lifetimes are found to be tau/sub D/sup 0/ = 4.7/sub -0.8//sup +0.9/ +- 0.5 x 10/sup -13/ s; tau/sub D/sup + -// = 8.9/sub -2.7//sup +3.8/ +- 1.3 x 10/sup -13/ s. The ratio of these lifetimes, tau/sub D/sup 0///tau/sub D/sup + -// = 1.9/sub -0.7//sup +0.9/ +- 0.3, indicates that the decays of these mesons cannot be explained by the simple spectator model of charmed particle decay.

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center, CA (USA)
OSTI Identifier:
5648587
Report Number(s):
SLAC-279
ON: DE85014201
DOE Contract Number:
AC03-76SF00515; AC03-76SF00098
Resource Type:
Technical Report
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted. Thesis
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; D MESONS; LIFETIME; DRIFT CHAMBERS; ELECTRON-POSITRON INTERACTIONS; EXPERIMENTAL DATA; PEP STORAGE RINGS; BOSONS; CHARM PARTICLES; DATA; ELEMENTARY PARTICLES; HADRONS; INFORMATION; INTERACTIONS; LEPTON-LEPTON INTERACTIONS; MEASURING INSTRUMENTS; MESONS; MULTIWIRE PROPORTIONAL CHAMBERS; NUMERICAL DATA; PARTICLE INTERACTIONS; PROPORTIONAL COUNTERS; PSEUDOSCALAR MESONS; RADIATION DETECTORS; STORAGE RINGS; 645102* - High Energy Physics- Particle Interactions & Properties-Experimental- Weak Interactions & Properties

Citation Formats

Gladney, L.D. Measurement of the lifetimes of the neutral and charged D mesons. United States: N. p., 1985. Web. doi:10.2172/5648587.
Copy to clipboard
Gladney, L.D. Measurement of the lifetimes of the neutral and charged D mesons. United States. doi:10.2172/5648587.
Copy to clipboard
Gladney, L.D. Fri . "Measurement of the lifetimes of the neutral and charged D mesons". United States. doi:10.2172/5648587. https://www.osti.gov/servlets/purl/5648587.
Copy to clipboard
@article{osti_5648587,
title = {Measurement of the lifetimes of the neutral and charged D mesons},
author = {Gladney, L.D.},
abstractNote = {Results are presented on the use of a high-resolution drift chamber in the Mark II Detector at PEP to measure the lifetimes of D/sup 0/ and D/sup + -/ mesons produced in e/sup +/e/sup -/ annihilations at 29 GeV. Based on a sample of 74 events for the D/sup 0/ mesons and 23 events for the D/sup + -/ mesons, the lifetimes are found to be tau/sub D/sup 0/ = 4.7/sub -0.8//sup +0.9/ +- 0.5 x 10/sup -13/ s; tau/sub D/sup + -// = 8.9/sub -2.7//sup +3.8/ +- 1.3 x 10/sup -13/ s. The ratio of these lifetimes, tau/sub D/sup 0///tau/sub D/sup + -// = 1.9/sub -0.7//sup +0.9/ +- 0.3, indicates that the decays of these mesons cannot be explained by the simple spectator model of charmed particle decay.},
doi = {10.2172/5648587},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 01 00:00:00 EST 1985},
month = {Fri Mar 01 00:00:00 EST 1985}
}
Copy to clipboard
Technical Report:
View Technical Report (1.78 MB)
DOI:  10.2172/5648587
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

  • In an exposure of the SLAC Hybrid Facility (SHF) to a backward scattered laser beam, 136 charm events produced in ..gamma..p interactions at 20 GeV have been observed. The SHF 1 m bubble chamber was equipped with a High Resolution Optics camera in order to detect directly the production and decay of charm particles. After imposing rigorous cuts, 48 charged, 50 neutral, and 2 topologically ambiguous decays remain. Using a novel method for estimating the momentum of unconstrained decays, the D meson lifetimes from this sample are measured to be tau/sub D sup +-/ = (8.6 +- 1.3/sub -0.3//sup +0.8/)more » x 10/sup -13/ sec and tau/sub D/sup 0// = (6.1 +- 0.9 +- 0.3) x 10/sup -13/ sec with a ratio of R = tau/sub D sup +-//tau/sub D/sup 0// = (1.4 +- 0.3/sub -0.1//sup +0.2/). This value of R indicates the Spectator Model charm particle decay mechanism is the dominate piece in the D/sub +-/ and D/sup 0/ decay rates. Limits are placed on additional contributions to the D decay rates from other processes including W-Exchange, Final State Interactions, and Pauli Principle Interference. 34 refs., 41 figs.« less

  • Data collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC are used to study the lifetimes of the B{sup 0} and B{sup +} mesons. The data sample consists of 7.4 fb{sup {minus}1} collected near the Upsilon(4S) resonance. B{sup 0} and B{sup +} mesons are fully reconstructed in several exclusive hadronic decay modes to charm and charmonium final states. The B lifetimes are determined from the flight length difference between the two B mesons which are pair-produced in the Upsilon(4S) decay. The preliminary measurements of the lifetimes are tau{sub B0} = 1.506 {+-} 0.052 (stat) {+-} 0.029more » (syst) ps, tau{sub B+} = 1.602 {+-} 0.049 (stat) {+-} 0.035 (syst) ps, and of their ratio is tau{sub B+}/tau{sub B0} = 1.065 {+-} 0.044 (stat) {+-} 0.021 (syst).« less

  • Data collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC are used to study the lifetimes of the B{sup 0} and B{sup +} mesons. The data sample consists of 7.4 fb{sup -1} collected near the {Upsilon}(4S) resonance. B{sup 0} and B{sup +} mesons are fully reconstructed in several exclusive hadronic decay modes to charm and charmonium final states. The B lifetimes are determined from the flight length difference between the two B mesons which are pair-produced in the {Upsilon}(4S) decay. The preliminary measurements of the lifetimes are {tau}B{sup 0} = 1.506 {+-} 0.052 (stat) {+-} 0.029more » (syst) ps, {tau}B{sup +} = 1.602 {+-} 0.049 (stat) {+-} 0.035 (syst) ps, and of their ratio is {tau}B{sup +}/{tau}B{sup 0} = 1.065 {+-} 0.044 (stat) {+-} 0.021 (syst).« less

  • This dissertation presents a measurement of time-dependent CP-violating asymmetries and a measurement of the CP-odd parity fraction in the decay B{sup 0} {yields} D*{sup +} D*{sup -}. The measurements are derived from a data sample of 88 x 10{sup 6} B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory located at the Stanford Linear Accelerator Center. A one-dimensional angular analysis of the decay products measures the CP-odd fraction to be 0.063 {+-} 0.055(stat) {+-} 0.009(syst), indicating that the D*{sup +}D*{sup -} final state is mostly CP-even. The time-dependent CP asymmetry parameters Im({lambda}{sub +}) and |{lambda}{submore » +}| are determined from an analysis of the time-dependence of flavor-tagged B decays. One neutral B meson is fully reconstructed in a D*{sup +} D*{sup -} final state, while the other B is inclusively reconstructed in order to determine its flavor. The Standard Model predicts the CP asymmetry parameters Im({lambda}{sub +}) and |{lambda}{sub +}| to be sin2{beta} and 1, respectively, in the absence of penguin diagram contributions. They are determined to be 0.05 {+-} 0.29(stat) {+-} 0.10(syst) and 0.75 {+-} 0.19(stat) {+-} 0.02(syst), respectively, which corresponds to a 2.5 sigma deviation from Standard Model predictions with penguin contributions ignored.« less

  • ;
    No abstract prepared.