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Title: Search for b^0s oscillations in semileptonic b decays

Abstract

This note describes a search for B{sub s}{sup 0} oscillations using semileptonic B decays recorded by the CDF detector during Run II of the Fermilab Tevatron Collider on about 1 fb{sup -1} of data, as it was in April 2006. Opposite-side and same-side b flavor taggers are used in this analysis. First they measure the B{sup 0} oscillation frequency and calibrate opposite-side b flavor taggers on a sample of semileptonic B decays. A simultaneous analysis of B{sup 0} and B{sup +} decays to {ell}D{sup 0}, {ell}D{sup +} and {ell}D* final states has been performed. Beginning with tagger calibrations available from earlier analyses on the {ell} + SVT samples, they use the high statistic {ell}D sample to derive scale factors for predicted dilutions of the soft muon, soft electron and jet charge opposite-side taggers. Secondly they reconstruct B{sub s}{sup 0} {yields} {ell}{sup +}D{sub s}{sup -}X decays in three different D{sub s}{sup -} channels, namely {phi}{pi}{sup -}, K*{sup 0} K{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup -}. D mass, lepton-D mass and lifetime parameters for signal and backgrounds are determined with unbinned maximum likelihood fits. They validate their fitter and obtain sensitivity projections with toy Monte Carlo samples. The {Delta}m{sub s} sensitivity onmore » the semileptonic sample is 17.3 ps{sup -1}. With the combination of the semileptonic and hadronic analyses they observe a signature consistent with B{sub s}{sup 0} - {bar B}{sup s}{sup 0} oscillations. The probability that random tags background could fluctuate to mimic such a signature is 0.5%. Under the hypothesis that this is a signal for B{sub s}{sup 0} - {bar B}{sup s}{sup 0} oscillations, they measure {Delta}m{sub s} = 17.31{sub -0.18}{sup -0.33}(stat.) {+-} 0.07(syst.) ps{sup -1}.« less

Authors:
;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
899704
Report Number(s):
FERMILAB-PUB-06-514-E
TRN: US200711%%529
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ELECTRONS; FERMILAB COLLIDER DETECTOR; FERMILAB TEVATRON; HYPOTHESIS; LIFETIME; OSCILLATIONS; PROBABILITY; SENSITIVITY; STATISTICS; Experiment-HEP

Citation Formats

Gomez-Ceballos, Guillelmo, and /Cantabria Inst. of Phys. Search for b^0s oscillations in semileptonic b decays. United States: N. p., 2007. Web.
Gomez-Ceballos, Guillelmo, & /Cantabria Inst. of Phys. Search for b^0s oscillations in semileptonic b decays. United States.
Gomez-Ceballos, Guillelmo, and /Cantabria Inst. of Phys. Thu . "Search for b^0s oscillations in semileptonic b decays". United States. doi:. https://www.osti.gov/servlets/purl/899704.
@article{osti_899704,
title = {Search for b^0s oscillations in semileptonic b decays},
author = {Gomez-Ceballos, Guillelmo and /Cantabria Inst. of Phys.},
abstractNote = {This note describes a search for B{sub s}{sup 0} oscillations using semileptonic B decays recorded by the CDF detector during Run II of the Fermilab Tevatron Collider on about 1 fb{sup -1} of data, as it was in April 2006. Opposite-side and same-side b flavor taggers are used in this analysis. First they measure the B{sup 0} oscillation frequency and calibrate opposite-side b flavor taggers on a sample of semileptonic B decays. A simultaneous analysis of B{sup 0} and B{sup +} decays to {ell}D{sup 0}, {ell}D{sup +} and {ell}D* final states has been performed. Beginning with tagger calibrations available from earlier analyses on the {ell} + SVT samples, they use the high statistic {ell}D sample to derive scale factors for predicted dilutions of the soft muon, soft electron and jet charge opposite-side taggers. Secondly they reconstruct B{sub s}{sup 0} {yields} {ell}{sup +}D{sub s}{sup -}X decays in three different D{sub s}{sup -} channels, namely {phi}{pi}{sup -}, K*{sup 0} K{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup -}. D mass, lepton-D mass and lifetime parameters for signal and backgrounds are determined with unbinned maximum likelihood fits. They validate their fitter and obtain sensitivity projections with toy Monte Carlo samples. The {Delta}m{sub s} sensitivity on the semileptonic sample is 17.3 ps{sup -1}. With the combination of the semileptonic and hadronic analyses they observe a signature consistent with B{sub s}{sup 0} - {bar B}{sup s}{sup 0} oscillations. The probability that random tags background could fluctuate to mimic such a signature is 0.5%. Under the hypothesis that this is a signal for B{sub s}{sup 0} - {bar B}{sup s}{sup 0} oscillations, they measure {Delta}m{sub s} = 17.31{sub -0.18}{sup -0.33}(stat.) {+-} 0.07(syst.) ps{sup -1}.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}
  • A search for B{sup 0}{sub s}-{ovr B}{sup 0}{sub s} oscillations is performed in a sample of B{sup 0}{sub s} semileptonic decays collected using dilepton triggers at the Tevatron Collider during 1992{endash}1995. The B{sup 0}{sub s} is reconstructed using {phi} meson-lepton correlations; its initial production flavor is determined with the second lepton in the event. From a signal of 1068 with a B{sup 0}{sub s} purity of 61{percent} , we obtain a limit on the B{sup 0}{sub s}-{ovr B}{sup 0}{sub s} oscillation frequency of {Delta}m{sub s}{gt}5.8 ps{sup {minus}1} at 95{percent} confidence level. {copyright} {ital 1999} {ital The American Physical Society}
  • A search for B{sub s}{sup 0}-{ovr B}{sub s}{sup 0} oscillations is performed in a sample of B{sub s}{sup 0} semileptonic decays collected using dilepton triggers at the Tevatron Collider during 1992-1995. The B{sub s}{sup 0} is reconstructed using phiv meson-lepton correlations; its initial flavor is determined with the second lepton in the event. From a signal of 1068 with a B{sub s}{sup 0} purity of 61%, we obtain a limit on the B{sub 2}{sup 0}-{ovr B}{sub s}{sup 0} oscillation frequency of {Delta}m{sub s}>5.8 ps{sup -1} at 95% confidence level.
  • Using a sample of 935 000 [ital B[bar B]] pairs collected with the CLEO-II detector at the Cornell Electron Storage Ring, we have obtained upper limits on the branching ratios for the [ital b][r arrow][ital ul][sup [minus]][bar [nu]] processes [ital B][sup [minus]][r arrow][omega][ital l][sup [minus]][bar [nu]], [ital B][sup [minus]][r arrow][rho][sup 0][ital l[minus]][bar [nu]], and [ital [bar B]][sup 0][r arrow][rho][sup +][ital l[minus]][bar [nu]]. The combined result using the relationships among the widths for these three modes is [ital B]([ital B][sup [minus]][r arrow][rho][sup 0][ital l[minus]][bar [nu]])[lt](1.6--2.7)[times]10[sup [minus]4] at 90% C.L., where the range of values is due to model dependence of themore » detection efficiencies. These measurements yield the limits [vert bar][ital V][sub [ital u][ital b]]/[ital V][sub [ital c][ital b]][vert bar][lt]0.08--0.13.« less
  • Using a sample of 935000 B{bar B} pairs a search has been performed for the exclusive b{r_arrow}u semileptonic decays B{r_arrow}{rho}{ell}{nu}, B{r_arrow}{omega}{ell}{nu}, and B{r_arrow}{eta}{ell}{nu}. The authors report on upper limits for these branching fractions and the implications for the Cabibbo-Kobayashi-Maskawa matrix element V{sub ub}.
  • We have performed a search for CP violation in a sample of semileptonic B{sub s}{sup 0} decays corresponding to approximately 5 fb{sup -1} of data collected by the D0 detector in Run II at the Fermilab Tevatron Collider. A time-dependent fit to the distributions of the B{sub s}{sup 0} candidates yields the flavor-specific asymmetry a{sub fs}{sup s} = [-1.7 {+-} 9.1(stat){sub -2.3}{sup +1.2}(syst)] x 10{sup -3}. This is the most precise measurement to date of this CP violation parameter.