Measurement of CKM-angle gamma with Charmed B0 Meson Decays (open access)

Measurement of CKM-angle gamma with Charmed B0 Meson Decays

This thesis reports measurements of the time-dependent CP asymmetries in fully reconstructed B{sup 0} {yields} (D{sup (*){-+}} and B{sup 0} {yields} D{sup {-+}} {rho}{sup {+-}}) decays in approximately 232 million {Upsilon}(4S) {yields} B{bar B} events, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the Stanford Linear Accelerator Center in California, as published in Ref. [14]. The phenomenon of CP violation allows one to distinguish between matter and antimatter, and, as such, is one of the essential ingredients needed to explain the apparent abundance of matter over antimatter in the universe. The Standard Model describes the observed elementary particles in terms of three generations of quarks and leptons, as well as the weak, electromagnetic, and strong interactions between them. In the Standard Model, CP violation is incorporated in the Cabibbo-Kobayashi-Maskawa (CKM) matrix, which describes the weak interactions between the quarks. The weak interactions between quarks are described by coupling constants that are functions of three real parameters and one irreducible complex phase. The magnitude of all CP violating effects in the Standard Model is related to this complex phase. The measurement of the CP violating phase of the CKM matrix is an important part of the present …
Date: July 17, 2007
Creator: Baak, Max Arjen & /Vrije U., Amsterdam
System: The UNT Digital Library
Measurement of the Inclusive Branching FractionsB(B^- to D^+ Pi^- Pi^-) and B(B^- to D*^+ Pi^- Pi^-) (open access)

Measurement of the Inclusive Branching FractionsB(B^- to D^+ Pi^- Pi^-) and B(B^- to D*^+ Pi^- Pi^-)

The D{sub J}{sup 0} is a family of four orbitally excited mesons: D*{sub 2}(2460){sup 0}, D{sub 1}(2420){sup 0}, D{sub 1}(j = 1/2){sup -}, and D*{sub 0}(j = 1/2){sup 0}. This dissertation presents the measurements of the inclusive branching fractions, {Beta}(B{sup -} {yields} D*{sup +}{pi}{sup -}{pi}{sup -}) and {Beta}(B{sup -} {yields} D{sup +}{pi}{sup -}{pi}{sup -}). The D{sub J}{sup 0} provides an intermediate resonance for those two modes. The data used for this analysis consists of Runs 1-5 with total integrated luminosity of 343.38 fb{sup -1}, which is corresponding to 383.92 million B{bar B} pairs, provided by the BABAR detector at the PEP-II asymmetric B Factory. The values presented are: {Beta}(B{sup -} {yields} D{sup +}{pi}{sup -}{pi}{sup -}) = (1.12 {+-} 0.02 {+-} 0.08) x 10{sup -3}; {Beta}(B{sup -} {yields} D*{sup +}{pi}{sup -}{pi}{sup -}) = (1.67 {+-} 0.03 {+-} 0.13) x 10{sup -3}.
Date: July 17, 2007
Creator: Eschenburg, Vance Onno & U., /Mississippi
System: The UNT Digital Library
Measurements of Branching Fraction and CP Violation inB Meson Rare Decays to Final States containing eta or eta' Mesons in the BaBar Experiment at SLAC (open access)

Measurements of Branching Fraction and CP Violation inB Meson Rare Decays to Final States containing eta or eta' Mesons in the BaBar Experiment at SLAC

Note that the main goal of this thesis work is the measurement of the branching fractions, charge asymmetry, and Time-Dependent CP Violation in {eta}'K{sup 0} mode. All other measurements are reported here for completion because they are connected by similar physics arguments. They are part of the Milan analysis activity, done by undergraduate students. They should not be considered as done in this thesis work. The measurements of the two body-modes {eta}{eta}, {eta}{phi}, and {eta}'{phi} are used to determine a theoretical bound based on SU(3) flavor symmetry for the difference between SM prediction and the experimental measurements of CP violation parameters in b {yields} s loop-dominated modes. In general for this estimation we need to measure the branching fractions (or upper limits) of neutral B decays to two-body modes with {eta}', {eta}, {phi}, {omega}, {pi}{sup 0}, K{sup 0}, K*{sup 0} [13, 14, 15, 16]. There is an important issue related to the branching fractions of {eta}'K (charged and neutral) modes. Since the discover of B {yields} {eta}'K in 1997 [17] with high branching fraction (higher than expected), it was found that the corresponding mode with {eta} is suppressed. This fact was pointed out by Lipkin in 1991 [18]. In particular, …
Date: July 17, 2007
Creator: Lazzaro, Alfio & U., /Milan
System: The UNT Digital Library
Mesure DU Rapport D'Embranchement ET DU Facteur Deforme DE La D_Sint_Gration b0 to Pilnu, ET D_Termination DE |Vub| Avec Unetechnique DE Reconstruction Rel_Ch_E DU Neutrinoac (open access)

Mesure DU Rapport D'Embranchement ET DU Facteur Deforme DE La D_Sint_Gration b0 to Pilnu, ET D_Termination DE |Vub| Avec Unetechnique DE Reconstruction Rel_Ch_E DU Neutrinoac

The authors report the results of a study of the exclusive charmless semileptonic decay, B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}, undertaken with approximately 227 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 an innovative loose neutrino reconstruction technique. They obtain partial branching fractions in 12 bins of q{sup 2}, the momentum transfer squared, from which they extract the f{sub +}(q{sup 2}) form-factor shape and the total branching fraction {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.46 {+-} 0.07{sub stat} {+-} 0.08{sub syst}) x 10{sup -4}. Based on a recent unquenched lattice QCD calculation of the form factor in the range q{sup 2} > 16 GeV{sup 2}/c{sup 4}, they find the magnitude of the CKM matrix element |V{sub ub}| to be (4.1 {+-} 0.2{sub stat} {+-} 0.2{sub syst{sub -0.4}{sup +0.6}FF}) x 10{sup -3}, where the last uncertainty is due to the normalization of the form factor.
Date: July 17, 2007
Creator: Cote, David & U., /Montreal
System: The UNT Digital Library
Search for the Rare Decay B to pi l+l- in the BaBar Experiment (open access)

Search for the Rare Decay B to pi l+l- in the BaBar Experiment

The rare decay B {yields} {pi}{ell}{sup +}{ell}{sup -} is the simplest manifestation of a b {yields} d{ell}{sup +}{ell}{sup -} flavor-changing neutral current (FCNC) process. This type of process only proceeds through penguin loop or box diagrams and is sensitive to physics at the electroweak scale. It can be used to constrain parameters of the Standard Model and its extensions. B {yields} {pi}{ell}{sup +}{ell}{sup -} events have not yet been observed; the branching fraction is expected to be an order of magnitude smaller than the measured branching fraction for the similar B {yields} K{ell}{sup +}{ell}{sup -} decay. Using 230 million B{bar B} meson pairs collected with the BABAR detector, we have done a search for the rare decay B {yields} {pi}{ell}{sup +}{ell}{sup -}. The data was produced in e+e? collision at the {Upsilon}(4S) resonance in the PEP-II collider between 1999 and 2004. Four exclusive B-meson decay modes have been reconstructed: B{sup +} {yields} {pi}{sup +}{ell}{sup +}{ell}{sup -} and B{sup 0} {yields} {pi}{sup 0}{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either an electron pair (e{sup +}e{sup -}) or a muon pair ({mu}{sup +}{mu}{sup -}). We find no evidence for a signal, and we obtain upper limits on the branching fractions {Beta}. …
Date: July 17, 2007
Creator: Ofte, Ingrid
System: The UNT Digital Library
Study of the Systems Ds+ Pi+ Pi+, Ds+ Pi- And Ds+ Pi+ in C Anti-C Fragmentation (open access)

Study of the Systems Ds+ Pi+ Pi+, Ds+ Pi- And Ds+ Pi+ in C Anti-C Fragmentation

None
Date: July 17, 2007
Creator: Pelizaeus, Marc & /Ruhr U., Bochum
System: The UNT Digital Library
Time Dependent CP Asymmetries and Branching RatioMeasurements in Charmless Three Body B Decays at BABAR (open access)

Time Dependent CP Asymmetries and Branching RatioMeasurements in Charmless Three Body B Decays at BABAR

In this work we presented measurements of CP violation and decay rates of B decays in final states not involving a charm quark in the final state. In particular, the time-dependent CP asymmetries of decays which proceed through b {yields} s elementary transition is a particularly sensitive probe of physics beyond the Standard Model. In fact, even if the precise measurements of CP conserving and CP violating processes show the success of the CKM picture of the flavour physics, the sector of b {yields} s transitions is still not strongly constrained and leaves room for new physics contributions. In particular, we considered the decays which have the cleanest theoretical prediction within the Standard Model: B{sup 0} {yields} {phi}K{sup 0} and B{sup 0} {yields} K{sub s}{sup 0}K{sub s}{sup 0}K{sub s}{sup 0} {beta}{sub eff}{sup SM} = 0.379. We examined the former with a completely new approach with respect to the past: the study of CP violation in the whole K{sup +}K{sup -}K{sup 0} phase space through a time-dependent Dalitz plot analysis. With this approach, we simultaneously measured the CP-violating asymmetries of the {phi}KJ{sup 0}, f{sub 0}(980)K{sup 0} resonant and K{sup +}K{sup -}K{sup 0} non-resonant contributions, avoiding one of the largest uncertainties which …
Date: July 17, 2007
Creator: Di Marco, Emanuele & U., /Rome
System: The UNT Digital Library
Resonant Inelastic X-ray Scattering of Rare-Earth and CopperSystems (open access)

Resonant Inelastic X-ray Scattering of Rare-Earth and CopperSystems

Rare earths and copper systems were studied using X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). The use of monochromased synchotron radiation and improved energy resolution for RIXS made possible to obtain valuable information on the electronic structure in 4f, 5f and 3d systems. Experimental results for rare-earths (Ho, Gd, Cm, U, Np, Pu) were analyzed by atomic multiplet theory based on the Hartree-Fock calculations. The inelastic scattering structures in RIXS spectra at 5d edge of actinides found to be sensitive to actinide oxidation states in different systems. Comparison of experimental and calculated Cm 5d RIXS spectra gave direct information about valency of the 248-curium isotope in oxide. Scientific understanding of processes that control chemical changes of radioactive species from spent fuel is improved by studying interactions of actinide ions (U, Np, Pu) with corroded iron surfaces. RIXS measurements at the actinide 5d edge found to be sensitive to actinide oxidation states in different systems. Comparison of experimental and calculated Cm 5d RIXS spectra gave direct information about valency of the 248 curium isotope in oxide. Scientific understanding of processes that control chemical changes of radioactive species from spent fuel is improved by studying interactions of actinide ions …
Date: July 11, 2007
Creator: Kvashnina, Kristina
System: The UNT Digital Library
Dalitz Analysis of D0 to K0(S) Pi+ Pi- and Measurement of the CKM Angle Gamma in Charged B+- Decays to D(*) K+- Decays (open access)

Dalitz Analysis of D0 to K0(S) Pi+ Pi- and Measurement of the CKM Angle Gamma in Charged B+- Decays to D(*) K+- Decays

Despite more than thirty years having elapsed since the discovery of CP violation, our understanding about the source and the nature of this phenomenon is still very limited. In the standard model of particle physics, CP violation is due to the presence of an non-irreducible weak phase in the Cabibbo-Kabayashi-Maskawa(CKM) matrix. Up to now, all the experimental results are in good agreement with the standard model. However, it is important for us to over-constrain the CKM quark-mixing matrix and explore the possibility of new physics beyond the standard model. The B meson provides an ideal place to measure CP violation due to its heavy mass and potentially large CP-violating effects. In particular, the angle {gamma} of the Unitary Triangle relating the elements of the CKM matrix is extremely crucial in terms of CP violation and constraints on the new physics models. Various methods using B{sup -} {yields} D{sup 0}K{sup -} decays have been proposed to measure based on the interference between the V{sub cb} and V{sub ub} amplitudes. Despite the simple concept, the measurement turns out to be experimentally challenging due to the small branching fraction and the small value of {tau}{sub B}, the amplitude ratio between the two contributing …
Date: July 10, 2007
Creator: Lau, Yan-Pan
System: The UNT Digital Library
Measurement of Branching Fractions and CP-Violating Asymmetries in B0 to K0K0bar and B+ to K0barK+ Decays at the BaBar Experiment (open access)

Measurement of Branching Fractions and CP-Violating Asymmetries in B0 to K0K0bar and B+ to K0barK+ Decays at the BaBar Experiment

Over the last few years, the B factories have established the Cabbibo-Kobayashi-Maskawa mechanism of CP violation in the Standard Model through the study of the decays of B mesons. The focus of Belle and BaBar has now expanded to the search for signatures of new physics beyond the Standard Model, particularly through examination of flavor-changing neutral-current transitions, which proceed through diagrams involving virtual loops. These decays are suppressed in the Standard Model, increasing sensitivity to new-physics effects but decreasing branching fractions. Exploiting large and growing datasets, BaBar and Belle have made many measurements in loop decays where a b quark transitions to an s quark, observing hints of possible deviations from Standard Model expectations in CP-violating measurements.
Date: July 10, 2007
Creator: Biesiada, Jedrzej
System: The UNT Digital Library
A Measurement of the Rate of Muon Capture in Hydrogen Gas andDetermination of the Proton's Induced Pseudoscalar Coupling gP (open access)

A Measurement of the Rate of Muon Capture in Hydrogen Gas andDetermination of the Proton's Induced Pseudoscalar Coupling gP

This dissertation describes a measurement of the rate ofnuclear muon capture by the proton, performed by the MuCap Collaborationusing a new technique based on a time projection chamber operating inultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPapressure. The hydrogen target's low gas density of 1 percent compared toliquid hydrogen is key to avoiding uncertainties that arise from theformation of muonic molecules. The capture rate was obtained from thedifference between the mu- disappearance rate in hydrogen--as determinedfrom data collected in the experiment's first physics run in fall2004--and the world averagefor the mu+ decay rate. After combining theresults of my analysis with the results from another independent analysisof the 2004 data, the muon capture rate from the hyperfine singlet groundstate of the mu-p atom is found to be Lambda_S = 725.0 +- 17.4 1/s, fromwhich the induced pseudoscalar coupling of the nucleon, gP(q2 = -0.88m2mu)= 7.3 +- 1.1, is extracted. This result for gP is consistent withtheoretical predictions that are based on the approximate chiral symmetryof QCD.
Date: July 10, 2007
Creator: Banks, Thomas Ira
System: The UNT Digital Library
Antiproton Structure Function in P-Pbar Diffractive Interactions at Sqrt(s) = 1.96 Tev (open access)

Antiproton Structure Function in P-Pbar Diffractive Interactions at Sqrt(s) = 1.96 Tev

None
Date: July 1, 2007
Creator: Malbouisson, Helena & U., /Rio de Janeiro State
System: The UNT Digital Library
Calibration of new flavor tagging algorithms using Bs oscillations (open access)

Calibration of new flavor tagging algorithms using Bs oscillations

Over the past decades the current theoretical description, the Standard Model of elementary particle physics, was solidified by many measurements as the basic theory describing fundamental particles and their interactions. It is extremely successful in explaining the high-precision data collected by experiments so far. The Standard Model includes several intrinsic parameters which have to be measured in experiments. Independent analyses of different physical processes can constrain those parameters. By combining those measurements physicists might be sensitive to physics beyond the Standard Model. If they are inconsistent it allows to get a hint on the theory that might supersede the Standard Model. The goal of the analysis presented in this thesis is to measure some of these parameters in the B{sub s} meson system. The B{sub s} meson, consisting of an anti-b and s quark, is not a pure mass eigenstate, thus allowing a B{sub s} meson to oscillate into its antiparticle via weak interacting processes. This is a general feature of any neutral meson. The history of meson mixing measurements is more then 50 years old. It was first observed in the kaon system. The oscillation in the B{sub d} system was measured very precisely by the B factories, whereas …
Date: July 1, 2007
Creator: Mack, Philipp
System: The UNT Digital Library
Diffractive J/Psi Production (open access)

Diffractive J/Psi Production

This work presents measurements of two diffractive production ratio for heavy flavour physics with the use of a reconstructed J/{psi} {yields} {mu}{sup +}{mu}{sup -} sample in p{bar p} collisions at {radical}s = 1.96 TeV using the D0 detector at Fermilab Tevatron. These events were selected using the Luminosity Monitor detectors, the calorimeter system and the muon system in a pseudo-rapidity region with range 2.7 {le} |{eta}| {le} 4.4. The measured ratio were estimated to be N{sub diff}{sup J/{psi}}/N{sub total}{sup J/{psi}} = (1.74 {+-} 0.16(stat) {+-} 0.13(syst))% e N{sub diff}{sup b}/N{sub total}{sup b} = (0.79 {+-} 0.11(stat) {+-} 0.23(syst))%.
Date: July 1, 2007
Creator: Assis Jesus, Ana Carolina & U., /Rio de Janeiro Federal
System: The UNT Digital Library
Diffractive Z/gamma* --> mu+mu- boson production in proton - antiproton collisions (open access)

Diffractive Z/gamma* --> mu+mu- boson production in proton - antiproton collisions

Measurements of the inclusive diffractive Z {yields} {mu}{sup +}{mu}{sup -} cross section with gap requirement for M{sub {mu}}{sub {mu}} > 40 GeV at {radical} s = 1.96 TeV and fraction of Z bosons produced diffractively with gap requirement from Z inclusive production are presented. The measurements are performed using a data sample corresponding to an integrated luminosity of 820 pb{sup -1}, collected with the D0 detector at the Tevatron, between 2002 to 2005. A total of 39945 di-muons events are selected and final results of: {sigma}{sub Diff}{sup gap} x Br(Z/{gamma}* {yields} {mu}{sup +}{mu}{sup -}) = 4.09 {+-} 0.64(stat.) {+-} 0.88(syst.) {+-} 0.27(lumi.) pb and, R{sub Diff}{sup gap} = 1.92 {+-} 0.30(stat.) {+-} 0.41(syst.) {+-} 0.12(lumi) % are obtained. In addition, d{sigma}/d{zeta} and d{sigma}/dy distributions are presented and they are compared with diffractive montecarlo (POMWIG). A reasonable agreement is obtained in this comparation. Finally, comparison of fraction of Z bosons produced diffractively with gap requirement (gap fraction) as measured with D0 during Run I of the Tevatron is compared. A good agreement is found for gap fraction results.
Date: July 1, 2007
Creator: Mendoza Navas, Luis Miguel
System: The UNT Digital Library
Measurement of Pi-K Ratios from the NuMI Target (open access)

Measurement of Pi-K Ratios from the NuMI Target

Interactions of protons (p) with the NuMI (Neutrinos at the Main Injector) target are used to create the neutrino beam for the MINOS (Main Injector Neutrino Oscillation Search) Experiment. Using the MIPP (Main Injector Particle Production) experimental apparatus, the production of charged pions and kaons in p+NuMI interactions is studied. The data come from a sample of 2 x 10{sup 6} events obtained by MIPP using the 120 GeV/c proton beam from the Main Injector at Fermi National Accelerator Laboratory in Illinois, USA. Pions and kaons are identified by measurement in a Ring Imaging Cherenkov detector. Presented are measurements of {pi}{sup -}/{pi}{sup +}, K{sup -}/K{sup +}, {pi}{sup +}/K{sup +} and {pi}{sup -}/K{sup -} production ratios in the momentum range p{sub T} < 2 GeV/c transversely and 20 GeV/c < p{sub z} < 90 GeV/c longitudinally. Also provided are detailed comparisons of the MIPP NuMI data with the MIPP Thin Carbon data, the MIPP Monte Carlo simulation and the current MINOS models in the relevant momentum ranges.
Date: July 1, 2007
Creator: Seun, Sin Man & U., /Harvard
System: The UNT Digital Library
Measurement of single top quark production at D0 using a matrix element method (open access)

Measurement of single top quark production at D0 using a matrix element method

Until now, the top quark has only been observed produced in pairs, by the strong force. According to the standard model, it can also be produced singly, via an electroweak interaction. Top quarks produced this way provide powerful ways to test the charged-current electroweak interactions of the top quark, to measure |V{sub tb}|, and to search for physics beyond the standard model. This thesis describes the application of the matrix element analysis technique to the search for single top quark production with the D0 detector using 0.9 fb{sup -1} of Run II data. From a comparison of the matrix element discriminants between data and the background model, assuming a Standard Model s-channel to t-channel cross section ratio of {sigma}{sub s}/{sigma}{sub t} = 0.44, we measure the single top quark production cross section: {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.8{sub -1.4}{sup +1.6} pb. This result has a p-value of 0.08%, corresponding to a 3.2 standard deviation Gaussian equivalent significance.
Date: July 1, 2007
Creator: Mitrevski, Jovan Pavle
System: The UNT Digital Library
A measurement of the lambda_b lifetime at the D0 experiment (open access)

A measurement of the lambda_b lifetime at the D0 experiment

This thesis describes a measurement of the lifetime of the {Lambda}{sub b}{sup 0} baryon, performed using data from proton-antiproton collisions at a centre of mass energy of 1.96 TeV. The decay {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{mu}{sup -}{ovr P{nu}}{sub {mu}}X was reconstructed in approximately 1.3 fb{sup -1} of data recorded by the D0 detector in 2002-2006 during Run II of the Fermilab Tevatron collider. A signal of 4437 {+-} 329 {Lambda}{sub c}{sup +}{mu}{sup -} pairs was obtained, and the {Lambda}{sub b}{sup 0} lifetime was measured using a binned {chi}{sup 2} fit, which gives a value {tau}({Lambda}{sub b}{sup 0}) = 1.290{sub -0.110}{sup +0.119}(stat){sub -0.091}{sup +0.085}(syst) ps. This result is consistent with the world average and is one of the most precise measurements of this quantity.
Date: July 1, 2007
Creator: Lewin, Marcus Philip
System: The UNT Digital Library