Observation of B0 ØØK0 and Study of B Meson Decays to the Five Kaons Final State PDF Download

Author: 董彥緯
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Category :
Languages : en
Pages :

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Author: Tetiana B. Hryn'ova
Publisher:
ISBN:
Category :
Languages : en
Pages : 165

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B mesons are unique among well-established non-quarkonium mesons in their ability to decay into baryons. Baryonic B decays offer a wide range of interesting areas of study: they can be used to test our theoretical understanding of rare decay processes involving baryons, search for direct CP violation and study low-energy QCD. This thesis presents measurements of branching fractions and a study of the decay dynamics of the charmless three-body decays of B meson into p{bar p}h final states, where h = {pi}{sup +}, K{sup +}, K{sub S}{sup 0}, K*{sup 0} or K*{sup +}. With a sample of 232 million {Upsilon}(4S) {yields} B{bar B} events collected with the BaBar detector, we report the first observation of the B {yields} p{bar p}K*{sup 0} decay, and provide improved measurements of branching fractions of the other modes. The distribution of the three final-state particles is of particular interest since it provides dynamical information on the possible presence of exotic intermediate states such as the hypothetical pentaquark states {Theta}*{sup ++} and {Theta}{sup +}in the m{sub pK{sup +}} and m{sub pK{sub S}{sup 0}} spectra, respectively, or glueball states (such as the tensor glueball f{sub J}(2220)) in the m{sub p{bar p}} spectrum. No evidence for exotic states is found and upper limits on the branching fractions are set. An enhancement at low p{bar p} mass is observed in all the B {yields} p{bar p}h modes, and its shape is compared between the decay modes and with the shape of the time-like proton form factor. A Dalitz plot asymmetry in B {yields} p{bar p}K{sup +} mode suggests dominance of the penguin amplitude in this decay and disfavors the possibility that the low mass p{bar p} enhancement originates from the presence of a resonance below threshold (such as the recently seen baryonium candidate at 1835 MeV/c{sup 2}). We also identify decays of the type B {yields} X{sub c{bar c}}h {yields} p{bar p}h, where h = K{sup +}, K{sub S}{sup 0}, K*{sup 0} or K*{sup +}, and X{sub c{bar c}} = {eta}{sub c} or J/{psi}. In particular, we report on the evidence of the B {yields} {eta}{sub c}K*{sup +} decay and provide a measurement of the width of {eta}{sub c}.

Author:
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Category :
Languages : en
Pages : 208

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A study of B-meson decays to final states with a single charm baryon is presented based on data recorded by the BABAR detector at the Stanford Linear Accelerator Center. Although the B meson is the lightest bottom-flavored meson, it is heavy enough to decay to a baryon made of three quarks and an antibaryon made of three antiquarks. By studying the baryonic weak decays of the B meson, we can investigate baryon production mechanisms in heavy meson decays. In particular, we measure the rates of the decays B- → [Lambda]+c$\bar{p}$[pi]- and $\bar{B}$0 → [Lambda]+c$\bar{p}$. Comparing these rates, we confirm an observed trend in baryonic B decays that the decay with the lower energy release, B- → [Lambda]+c$\bar{p}$[pi]-, is favored over $\bar{B}$0 → [Lambda]+c$\bar{p}$. The dynamics of the baryon-antibaryon ([Lambda]+c$\bar{p}$) system in the three-body decay also provide insight into baryon-antibaryon production mechanisms. The B- → [Lambda]+c$\bar{p}$[pi]- system is a laboratory for searches for excited #c baryon states; we observe the resonant decays B- → [Sigma]c(2455) 0$\bar{p}$ and B- → [Sigma]c(2800) 0$\bar{p}$. This is the first observation of the decay B- → [Sigma]c(2800) 0$\bar{p}$; however, the mass of the observed #c(2800)0 state is inconsistent with previous measurements. Finally, we examine the angular distribution of the B- → [Sigma]c(2455) 0$\bar{p}$ decays and measure the spin of the B- → [Sigma]c(2455) 0$\bar{p}$ baryon to be J = 1/2, as predicted by the quark model.

Author:
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Category :
Languages : en
Pages : 9

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We have studied two-body charmless hadronic decays of B mesons into the final states??, K?, and KK. Using 3.3 million B{bar B} pairs collected with the CLEO-II detector, we have made the first observation of the decays B° → K?−, B+ → K°?+, and the sum of B+ →?+?° and B+ → K+?° decays (an average over charge-conjugate states is always implied). We place upper limits on branching fractions for the remaining decay modes.

Author: Tetiana B. Hryn'ova
Publisher:
ISBN:
Category :
Languages : en
Pages : 147

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Author: Stephanie A. Majewski
Publisher:
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Category :
Languages : en
Pages : 218

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Author:
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Category :
Languages : en
Pages : 8

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We present measurements of B meson decays to the final states [omega]K*, [omega][rho], and [omega]f0, where K* indicates a spin 0, 1, or 2 strange meson. The data sample corresponds to 465 x 106 B{bar B} pairs collected with the BABAR detector at the PEP-II ee− collider at SLAC. B meson decays involving vector-scalar, vector-vector, and vector-tensor final states are analyzed; the latter two shed new light on the polarization of these final states. We measure the branching fractions for nine of these decays; five are observed for the first time. For most decays we also measure the charge asymmetry and, where relevant, the longitudinal polarization f{sub L}.

Author: John Joseph O'Neill (Ph. D. in physics)
Publisher:
ISBN:
Category : Mesons
Languages : en
Pages : 143

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Author:
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Category :
Languages : en
Pages : 7

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Using 383 million B{bar B} pairs from the BABAR data sample, they report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to K{bar K}* or [eta][pi][pi] final states with mass in the range (1.2-1.8) GeV/c2. They observe a significant enhancement at the low K{bar K}* invariant mass which is interpreted as B 2K, find evidence for the decay B+ 2K+, and place upper limits on the decays B+ 2K+, B+ 2!f1(1285)K+, B+ 2!f1(1420)K+, and B+ 2K+.

Author: Sheldon Stone
Publisher: World Scientific
ISBN: 9789810213305
Category : Science
Languages : en
Pages : 502

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The study of b quarks has now reached a stage where it is useful to review what has been learned so far and also to look at the implications of future studies. The most important observations thus far measurement of the B lifetime, B0 B0 mixing, and the observation of b? u transitions, as well as more mundane results on hadronic and semileptonic transitions are described in detail by experimentalists who have been closely involved with the measurements. Theoretical progress in understanding b quark decays, including the mechanisms of hadronic and semileptonic decays, are described. Synthesizing the experimental and theoretical information, the authors discuss tests of the standard model and measurements of standard model parameters. Possibilities of more extensive tests using measurement of CP violation in the B system are also addressed.