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Title: First Physics Results at Babar

Abstract

The BABAR detector, which operates at the SLAC PEP-II asymmetric e{sup +}e{sup -} collider at energies near the {Upsilon}(4S) resonance, started operation on the 26th of May 1999. They present the first study of sin2{beta}, with samples of B{sup 0} {yields} J/{psi} K{sub s}{sup 0} and B{sup 0} {yields} {psi}(2S) K{sub 2}{sup 0} decays, using 9.0 fb{sup -1} of data recorded between January and July 2000 at the {Upsilon}(4S) resonance and 0.8 fb{sup -1} recorded 40 MeV below the {Upsilon}(4S) resonance. A preliminary result of sin2{beta} = 0.12 {+-} 0.37(stat) {+-} 0.09(syst) was obtained. Details of the analysis are given. Moreover, they present measurements of charged and neutral B meson lifetimes and B{sup 0}{bar B}{sup 0} oscillation frequency.

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center, Menlo Park, CA (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
784826
Report Number(s):
SLAC-PUB-8727
TRN: US0108791
DOE Contract Number:
AC03-76SF00515
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Dec 2000
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; B NEUTRAL MESONS; OSCILLATIONS; RESONANCE; PEP STORAGE RINGS; RADIATION DETECTORS; ELECTRON-POSITRON COLLISIONS; VECTOR MESONS

Citation Formats

Lodovico, Francesca. First Physics Results at Babar. United States: N. p., 2000. Web. doi:10.2172/784826.
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Lodovico, Francesca. First Physics Results at Babar. United States. doi:10.2172/784826.
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Lodovico, Francesca. Fri . "First Physics Results at Babar". United States. doi:10.2172/784826. https://www.osti.gov/servlets/purl/784826.
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@article{osti_784826,
title = {First Physics Results at Babar},
author = {Lodovico, Francesca},
abstractNote = {The BABAR detector, which operates at the SLAC PEP-II asymmetric e{sup +}e{sup -} collider at energies near the {Upsilon}(4S) resonance, started operation on the 26th of May 1999. They present the first study of sin2{beta}, with samples of B{sup 0} {yields} J/{psi} K{sub s}{sup 0} and B{sup 0} {yields} {psi}(2S) K{sub 2}{sup 0} decays, using 9.0 fb{sup -1} of data recorded between January and July 2000 at the {Upsilon}(4S) resonance and 0.8 fb{sup -1} recorded 40 MeV below the {Upsilon}(4S) resonance. A preliminary result of sin2{beta} = 0.12 {+-} 0.37(stat) {+-} 0.09(syst) was obtained. Details of the analysis are given. Moreover, they present measurements of charged and neutral B meson lifetimes and B{sup 0}{bar B}{sup 0} oscillation frequency.},
doi = {10.2172/784826},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Dec 01 00:00:00 EST 2000},
month = {Fri Dec 01 00:00:00 EST 2000}
}
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Technical Report:
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DOI:  10.2172/784826
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  • The BABAR detector, which operates at the SLAC PEP-II asymmetric e{sup +}e{sup -} collider at energies near the {Upsilon} (4S) resonance, started operation on the 26th of May 1999. They present the first study of sin2{beta}, with samples of B{sup 0} {yields} J/{psi} K{sub s}{sup 0} and B{sup 0} {yields} {psi}(2S) K{sub s}{sup 0} decays, using 9.0 fb{sup -1} of data recorded between January and July 2000 at the {Upsilon}(4S) resonance and 0.8 fb{sup -1} recorded 40 MeV below the {Upsilon}(4S) resonance. A preliminary result of sin2{beta} = 0.12 {+-} 0.37(stat) {+-} 0.09(syst) was obtained. Details of the analysis aremore » given. Moreover, they present measurements of charged and neutral B meson lifetimes and B{sup 0}{bar B}{sup 0} oscillation frequency.« less

  • The BaBar experiment and the PEP-II accelerator at SLAC started to take data on May 26, 1999. By the time of this conference, the recorded integrated luminosity was 20 fb{sup -1}, of which 8 fb{sup -1} were analyzed to provide a first set of physics results. This talk reviews the first measurement of sin 2{beta} and the study of B meson decays to charmonium modes and 2-body charmless decays. Complementary results were presented by the BaBar Collaboration at this conference and are reviewed in [1].

  • The authors present a preliminary measurement of time-dependent CP-violating asymmetries in B{sup 0} {yields} J/{psi}K{sub s}{sup 0} and B{sup 0} {yields} {psi}(2S)K{sub s}{sup 0} decay recorded by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. The data sample consists of 9.0 fb{sup -1} collected at the {Upsilon}(4S) resonance and 0.8 fb{sup -1} off-resonance. One of the neutral B mesons, produced in pairs at the {Upsilon}(4S), is fully reconstructed. The flavor of the other neutral B meson is tagged at the time of its decay, mainly with the charge of identified leptons and kaons. The time difference betweenmore » the decays is determined by measuring the distance between the decay vertices. Wrong-tag probabilities and the time resolution function are measured with samples of fully-reconstructed semileptonic and hadronic neutral B final states. The value of the asymmetry amplitude, sin2{beta}, is determined from a maximum likelihood fit to the time distribution of 120 tagged B{sup 0} {yields} J/{psi}K{sub s}{sup 0} and B{sup 0} {yields} {psi}(2S)K{sub s}{sup 0} candidates: sin2{beta} = 0.12 {+-} 0.37 (stat) {+-} 0.09 (syst).« less

  • We present a preliminary measurement of the branching fraction of the exclusive penguin decay B{sup 0} {yields} K*{sub {gamma}}{sup 0} using (8.6 {+-} 0.3) x 10{sup 6} B{bar B} decays B(B{sup 0} {yields} K*{sub {gamma}}{sup 0}) = (5.42 {+-} 0.82(stat.) {+-} 0.47(sys.)) x 10{sup -5}. In addition they search for the related penguin decays with a lepton pair in the final state, B{sup +} {yields} K{sup +}{ell}{sup +}{ell}{sup -}, B{sup 0} {yields} K*{sup 0} {ell}{sup +}{ell}{sup -}.

  • The BABAR experiment has been taking data since about one year. Physics results, complementary to those described in [1], are presented: various measurements of the neutral and charged B mesons lifetimes, the B{sup 0} mixing frequency, the mistag fractions, and the B {yields} D{sub s}{sup (*)}X and B{sup 0} {yields} D{sub s}{sup (*)+} D{sup *-} branching ratios. Some prospects for the close future are shown. All the numbers given here are preliminary.