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Top quark pair production cross section at the Tevatron

Description: Top quark pair production cross section has been measured at the Tevatron by CDF and D0 collaborations using different channels and methods, in order to test standard model predictions, and to search for new physics hints affecting the t{bar t} production mechanism or decay. Measurements are carried out with an integrated luminosity of 1.0 to 2.0 fb{sup -1}, and are found to be consistent with standard model expectations.
Date: April 1, 2008
Creator: Cortiana, Giorgio & /INFN, Padua /Padua U.
Partner: UNT Libraries Government Documents Department

Performance study of GPUs in real-time trigger applications for HEP experiments

Description: Graphical Processing Units (GPUs) have evolved into highly parallel, multi-threaded, multicore powerful processors with high memory bandwidth. GPUs are used in a variety of intensive computing applications. The combination of highly parallel architecture and high memory bandwidth makes GPUs a potentially promising technology for effective real-time processing for High Energy Physics (HEP) experiments. However, not much is known of their performance in real-time applications that require low latency, such as the trigger for HEP experiments. We describe an R and D project with the goal to study the performance of GPU technology for possible low latency applications, performing basic operations as well as some more advanced HEP lower-level trigger algorithms (such as fast tracking or jet finding). We present some preliminary results on timing measurements, comparing the performance of a CPU versus a GPU with NVIDIA's CUDA general-purpose parallel computing architecture, carried out at CDF's Level-2 trigger test stand. These studies will provide performance benchmarks for future studies to investigate the potential and limitations of GPUs for real-time applications in HEP experiments.
Date: June 1, 2011
Creator: Ketchum, W.; U., /Chicago; Amerio, S.; /INFN, Padua; Bastieri, D.; Bauce, M. et al.
Partner: UNT Libraries Government Documents Department

An Index for the Dirac Operator on D3 Brane withBackground Fluxes

Description: We study the problem of instanton generated superpotentials in Calabi-Yau orientifold compactifications directly in type IIB string theory. To this end, we derive the Dirac equation on a Euclidean D3 brane in the presence of background fluxes. We propose an index which governs whether the generation of a superpotential in the effective 4d theory by D3 brane instantons is possible. Applying the formalism to various classes of examples, including the K3 x T{sup 2}/Z{sub 2} orientifold, in the absence and presence of fluxes, we show that our results are consistent with conclusions attainable via duality from an M-theory analysis.
Date: August 3, 2005
Creator: Bergshoeff, Eric; U., /Groningen; Kallosh, Renata; /Stanford U., Phys. Dept. /Kyoto U., Yukawa Inst., Kyoto; Kashani-Poor, Amir-Kian; /Stanford U., Phys. Dept. /SLAC et al.
Partner: UNT Libraries Government Documents Department

Study of multi-muon events produced in p anti-p interactions at s**(1/2) = 1.96-TeV

Description: We report the results of a study of multi-muon events produced at the Fermilab Tevatron collider and acquired with the CDF II detector using a dedicated dimuon trigger. The production cross section and kinematics of events in which both muon candidates are produced inside the beam pipe of radius 1.5 cm are successfully modeled by known processes which include heavy flavor production. In contrast, we are presently unable to fully account for the number and properties of the remaining events, in which at least one muon candidate is produced outside of the beam pipe, in terms of the same understanding of the CDF II detector, trigger, and event reconstruction.
Date: June 12, 2010
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Partner: UNT Libraries Government Documents Department

The On-Orbit Calibrations for the Fermi Large Area Telescope

Description: The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.
Date: November 17, 2011
Creator: Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
Partner: UNT Libraries Government Documents Department

The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

Description: The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy {gamma}-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy {gamma}-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure spectra from 20 MeV to more than ...
Date: May 15, 2009
Creator: Atwood, W.B.; /UC, Santa Cruz; Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
Partner: UNT Libraries Government Documents Department

Design and Initial Tests of the Tracker-Converter ofthe Gamma-ray Large Area Space Telescope

Description: The Tracker subsystem of the Large Area Telescope (LAT) science instrument of the Gamma-ray Large Area Space Telescope (GLAST) mission has been completed and tested. It is the central detector subsystem of the LAT and serves both to convert an incident gamma-ray into an electron-positron pair and to track the pair in order to measure the gamma-ray direction. It also provides the principal trigger for the LAT. The Tracker uses silicon strip detectors, read out by custom electronics, to detect charged particles. The detectors and electronics are packaged, along with tungsten converter foils, in 16 modular, high-precision carbon-composite structures. It is the largest silicon-strip detector system ever built for launch into space, and its aggressive design emphasizes very low power consumption, passive cooling, low noise, high efficiency, minimal dead area, and a structure that is highly transparent to charged particles. The test program has demonstrated that the system meets or surpasses all of its performance specifications as well as environmental requirements. It is now installed in the completed LAT, which is being prepared for launch in early 2008.
Date: April 16, 2007
Creator: Atwood, W.B.; Bagagli, R.; Baldini, L.; Bellazzini, R.; Barbiellini, G.; Belli, F. et al.
Partner: UNT Libraries Government Documents Department

Observation of the Baryonic B decay B0bar to Lambda_c^+ anti-Lambda K-

Description: The authors report the observation of the baryonic B decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} with a significance larger than 7 standard deviations based on 471 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II storage ring at SLAC. They measure the branching fraction for the decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} to be (3.8 {+-} 0.8{sub stat} {+-} 0.2{sub sys} {+-} 1.0 {sub {Lambda}{sub c}{sup +}}) x 10{sup -5}. The uncertainties are statistical, systematic, and due to the uncertainty in the {Lambda}{sub c}{sup +} branching fraction. They find that the {Lambda}{sub c}{sup +} K{sup -} invariant mass distribution shows an enhancement above 3.5 GeV/c{sup 2}.
Date: November 8, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Fermi Large Area Telescope First Source Catalog

Description: Abstract Not Provided
Date: July 8, 2013
Creator: Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
Partner: UNT Libraries Government Documents Department

Search for CP Violation in the Decay D+/- to Ks pi+/-

Description: We report on a search for CP violation in the decay D{sup {+-}} {yields} K{sub S}{sup 0}{pi}{sup {+-}} using a data set corresponding to an integrated luminosity of 469 fb{sup -1} collected with the BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} storage rings. The CP-violating decay rate asymmetry A{sub CP} is determined to be (-0.44 {+-} 0.13(stat) {+-} 0.10(syst))%, consistent with zero at 2.7 {sigma} and with the standard model prediction of (-0.332 {+-} 0.006)%. This is currently the most precise measurement of this parameter.
Date: August 22, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Measurement of the gamma gamma* to eta_c transition form factor

Description: The authors study the reaction e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sub c}, {eta}{sub c} {yields} K{sub S}K{sup {+-}}{pi}{sup {-+}} and obtain {eta}{sub c} mass and width values 2982.2 {+-} 0.4 {+-} 1.6 MeV/c{sup 2} and 31.7 {+-} 1.2 {+-} 0.8 MeV, respectively. They find {Lambda}({eta}{sub c} {yields} {gamma}{gamma}){Beta}({eta}{sub c} {yields} K{bar K}{pi}) = 0.374 {+-} 0.009 {+-} 0.031 keV, and measure the {gamma}{gamma}* {yields} {eta}{sub c} transition form factor in the momentum transfer range from 2 to 50 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.
Date: April 28, 2010
Creator: Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J. et al.
Partner: UNT Libraries Government Documents Department

Observation of the Rare Decay B+ \to K+pi0pi0 and Measurement of the Quasi-two Body Contributions B+ \to K*(892)+pi0, B+ \to f0(980)K+ and B+ \to chic0K+

Description: We report an analysis of charmless hadronic decays of charged B mesons to the final state K{sup +}{pi}{sup 0}{pi}{sup 0}, using a data sample of (470.9 {+-} 2.8) x 10{sup 6} B{bar B} events collected with the BABAR detector at the {Gamma}(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be {Beta}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = (16.2 {+-} 1.2 {+-} 1.5) x 10{sup -6} and A{sub CP}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = -0.06 {+-} 0.06 {+-} 0.04, where the uncertainties are statistical and systematic, respectively. Additionally, we study the contributions of the B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0}, B{sup +} {yields} f{sub 0}(980)K{sup +}, and B{sup +} {yields} {chi}{sub c0}K{sup +} quasi-two-body decays. We report the world's best measurements of the branching fraction and CP asymmetry of the B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0} and B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0} channels.
Date: December 13, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Evidence for Direct CP Violation in the Measurement of the Cabibbo-Kobayashi-Maskawa Angle gamma with B-+ to D(*) K(*)-+ Decays

Description: We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle {gamma} through a Dalitz plot analysis of neutral D meson decays to K{sub S}{sup 0}{pi}{sup +}{pi}{sup -} and K{sub S}{sup 0} K{sup +}K{sup -} produced in the processes B{sup {-+}} {yields} DK{sup {-+}}, B{sup {-+}} {yields} D* K{sup {-+}} with D* {yields} D{pi}{sup 0}, D{gamma}, and B{sup {-+}} {yields} DK*{sup {-+}} with K*{sup {-+}} {yields} K{sub S}{sup 0}{pi}{sup {-+}}, using 468 million B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. We measure {gamma} = (68 {+-} 14 {+-} 4 {+-} 3){sup o} (modulo 180{sup o}), where the first error is statistical, the second is the experimental systematic uncertainty and the third reflects the uncertainty in the description of the neutral D decay amplitudes. This result is inconsistent with {gamma} = 0 (no direct CP violation) with a significance of 3.5 standard deviations.
Date: August 19, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Evidence for B+ --> tau+ nu_tau Decays using Hadronic B Tags

Description: We present a search for the decay B{sup +} --> {tau}{sup +} {nu}{sub {tau}} using 467.8 x 10{sup 6} B{anti B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with on completely reconstructed B{sup -} in an hadronic decay mode (B{sup -} --> D{sup (*)0}X{sup -} and B{sup -} --> J/{psi} X{sup -}). We examine the rest of the event to search for a B{sup +} --> {tau}{sup +} {nu}{sub {tau}} decay. We identify the {tau}{sup +} lepton in the following modes: {tau}{sup +} --> e{sup +} {nu}{sub e}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {mu}{sup +} {nu}{sub {mu}}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {pi}{sup +}{anti {nu}}{sub {tau}} and {tau}{sup +} --> {rho}{anti {nu}}{sub {tau}}. We find an excess of events with respect to expected background, which excludes the null signal hypothesis at the level of 3.3 {sigma} and can be converted to a branching fraction central value of B(B{sup +} --> {tau}{sup +} {nu}{sub {tau}})= (1.80{sup + 0.57}{sub - 0.54}(stat.) {+-} 0.26 (syst.)) x 10{sup -4}.
Date: August 11, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Measurement of the B0 ->&#960&#8722&#8467&#957and B ->&#951(&#8242)&#8467&#957Branching Fractions, the B0 ->&#960&#8722&#8467&#957and B ->&#951&#8467&#957Form-Factor Shapes, and Determination of |Vub|

Description: We report the results of a study of the exclusive charmless semileptonic decays, B{sup +} {yields} {eta}{sup {prime}}{ell}{sup +}{nu} and B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}, undertaken with approximately 464 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B{sup +} {yields} {eta}{ell}{sup +}{nu} and B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} decays in three and 12 bins of q{sup 2}, respectively, from which we extract the f{sub +}(q{sup 2}) form-factor shapes and the total branching fractions {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) = (0.36 {+-} 0.05{sub stat} {+-} 0.04{sub syst}) x 10{sup -4} and {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.42 {+-} 0.05{sub stat} {+-} 0.07{sub syst}) x 10{sup -4}. We also measure {Beta}(B{sup +} {yields} {eta}{sup {prime}}{ell}{sup +}{nu}) = (0.24 {+-} 0.08{sub stat} {+-} 0.03{sub syst}) x 10{sup -4}. We obtain values for the magnitude of the CKM matrix element |V{sub ub}| using three different QCD calculations.
Date: August 12, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Measurement of the branching fraction for $\tau\to\eta K\nu_\tau$ and a search for second-class currents in $\tau\to\eta\pi\nu_\tau$ with $\eta\to\pi^ \pi^-\pi0$

Description: The authors report on analyses of tau lepton decays {tau}{sup -} {yields} {eta}K{sup -}{nu}{sub {tau}} and {tau}{sup -} {yields} {eta}{pi}{sup -}{nu}{sub {tau}}, with {eta} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}, using 470 fb{sup -1} of data from the BABAR experiment at PEP-II, collected at center-of-mass energies at and near the {Upsilon}(4S) resonance. They measure the branching fraction for the {tau}{sup -} {yields} {eta}K{sup -}{nu}{sub {tau}} decay mode, {Beta}({tau}{sup -} {yields} {eta}K{sup -}{nu}{sub {tau}}) = (1.42 {+-} 0.11(stat) {+-} 0.07(syst)) x 10{sup -4}, and report a 95% confidence level upper limit for the second-class current process {tau}{sup -} {yields} {eta}{pi}{sup -}{nu}{sub {tau}}, {Beta}({tau}{sup -} {yields} {eta}{pi}{sup -}{nu}{sub {tau}}) < 9.9 x 10{sup -5}.
Date: August 12, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

A Search for the Rare Decay $B\rightarrow\gamma\gamma$

Description: We report the result of a search for the rare decay B{sup 0} {yields} {gamma}{gamma} in 426 fb{sup -1} of data, corresponding to 226 million B{sup 0}{bar B}{sup 0} pairs, collected on the {Upsilon}(4S) resonance at the PEP-II asymmetric-energy e{sup +}e{sup -} collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21{sub -12}{sup +13} signal events with a statistical signficance of 1.9 {sigma}. This corresponds to a branching fraction {Beta}(B{sup 0} {yields} {gamma}{gamma}) = (1.7 {+-} 1.1(stat.) {+-} 0.2(syst.)) x 10{sup -7}. Based on this result, we set a 90% confidence level upper limit of {Beta}(B{sup 0} {yields} {gamma}{gamma}) < 3.2 x 10{sup -7}.
Date: June 2, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

A Study of Radiative Bottomonium Transitions using Converted Photons

Description: The authors use (111 {+-} 1) million {Upsilon}(3S) and (89 {+-} 1) million {Upsilon}(2S) events recorded by the BABAR detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions betwen bottomonium states using photons that have been converted to e{sup +}e{sup -} pairs by the detector material. They observe {Upsilon}(3S) {yields} {gamma}{chi}{sub b0,2}(1P) decay, make precise measurements of the branching fractions for {chi}{sub b1,2}(1P, 2P) {yields} {gamma}{Upsilon}(1S) and {chi}{sub b1,2}(2P) {yields} {gamma}{Upsilon}(2S) decays, and search for radiative decay to the {eta}{sub b}(1S) and {eta}{sub b}(2S) states.
Date: August 15, 2011
Creator: Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J. et al.
Partner: UNT Libraries Government Documents Department

Search for Bbar to Lambda_c+ X l- nu Decays in Events with a Fully Reconstructed B Meson

Description: We present a search for semileptonic B decays to the charmed baryon {Lambda}{sub c}{sup +} based on 420 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. By fully reconstructing the recoiling B in a hadronic decay mode, we reduce non-B backgrounds and determine the flavor of the signal B. We statistically correct the flavor for the effect of the B{sup 0} mixing. We obtain a 90% confidence level upper limit of {Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X{ell}{sup -} {bar {nu}}{sub {ell}})/{Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X) < 3.5%.
Date: April 19, 2012
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Search for B+ meson decay to a1+ K*0

Description: We present a search for the decay B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892). The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represent 465 million B{anti B} pairs produced in e{sup +}e{sup -} annihilation at the energy of the {Upsilon}(4S). We find no significant signal and set an upper limit at 90% confidence level on the product of branching fractions B(B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892)) x B({alpha}{sup +}{sub 1}(1260) --> {pi}{sup +}{pi}{sup -}{pi}{sup +}) of 1.8 x 10{sup -6}.
Date: August 11, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Search for b --> u Transitions in B^{+-} --> [K^{-+} pi^{+-} pi0]_D K^{+-} Decays

Description: The authors present a study of the decays B{sup {+-}} {yields} DK{sup {+-}} with D mesons reconstructed in the K{sup +}{pi}{sup -}{pi}{sup 0} or K{sup -}{pi}{sup +}{pi}{sup 0} final states, where D indicates a D{sup 0} or a {bar D}{sup 0} meson. Using a sample of 474 million B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC, they measure the ratios R{sup {+-}} {triple_bond} {Lambda}(B{sup {+-}}{yields}[K{sup {-+}}{pi}{sup {+-}}{pi}{sup 0}]{sub D}K{sup {+-}})/{Lambda}(B{sup {+-}}{yields}[K{sup {+-}}{pi}{sup {-+}}{pi}{sup 0}]{sub D}K{sup {+-}}). They obtain R{sup +} = (5{sub -10}{sup +12}(stat){sub -4}{sup +2}(syst)) x 10{sup -3} and R{sup -} = (12{sub -10}{sup +12}(stat){sub -5}{sup +3}(syst)) x 10{sup -3}, from which they extract the upper limits at 90% probability: R{sup +} < 23 x 10{sup -3} and R{sup -} < 29 x 10{sup -3}. Using these measurements, they obtain an upper limit for the ratio r{sub B} of the magnitudes of the b {yields} u and b {yields} c amplitudes r{sub B} < 0.13 at 90% probability.
Date: August 12, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department