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

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 10

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Using data collected in the region of the?(4S) resonance with the CLEO-II detector, they report on the first observation of exclusive decays of the B meson to final states with a charmed baryon. They have measured the branching fractions?(B− →?{sub c}{bar p}?−) = (0.62{sub -0.20}{sup +0.23} ± 0.11 ± 0.10) x 10−3 and?({bar B}° →?{sub c}+{bar p}?+?−) = (1.33{sub -0.42}{sup +0.46} ± 0.31 ± 0.21) x 10−3. In addition, they report upper limits for final states of the form {bar B} →?{sub c}+{bar p}(n?) and?{sub c}+{bar p}(n?)?° where (n?) denotes up to four charged pions.

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

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Author: Arnau Brossa Gonzalo
Publisher: Springer Nature
ISBN: 3031227530
Category : Science
Languages : en
Pages : 241

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This book presents the latest results on the branching fraction and phase space distribution of B0 and Bs0 decays into final states including excited neutral charm mesons. This work represents four years of research, and the book describes in detail all the necessary steps and techniques required to perform a physics analysis of the data recorded by the LHCb experiment in the years 2016–2018. Although the results presented in this book represent the first measurement of such decays, the text is written in a manner accessible to Ph.D. students and early career researchers. Thus, all the contents included in this book are described in a pedagogical way, including technical details that would allow the results to be reproduced in future. In addition to the methodology used to perform these measurements, the book also includes a description of the theoretical background required to interpret the results presented, as well as a technical description of the LHCb detector, which provided the data sample used in this study.

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: Eric Ashton Eckhart
Publisher:
ISBN:
Category : Mesons
Languages : en
Pages :

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Abstract: We search for the decays of $B$ mesons to charmless final states involving a baryon and an anti-baryon using 9.2 fb -1 of e + e - annihilation data taken on the?(4s) resonance with the CLEO II and CLEO II. V detectors, and 6.2 fb -1 from CLEO III. We perform an extended maximum likelihood analysis of the data to determine signal yields. We report an observation of the decay mode B - -> p anti-p K - and measure its branching fraction to be (5.88 +2.86 -2.21 (stat.) +1.12 -0.19 (syst.)) x 10 -6 . We find no statistically significant signals for our other modes and establish 90% C.L. upper limits of BR(B -> p anti-p) 1.4 x 10 -6, BR(B - anti-p?) 1.5 x 10 -6, BR(B -? anti-?) 1.2 x 10 -6, and BR(B - anti-p?p +)

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 24

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We present results for B-meson decay modes involving a charm meson, protons, and pions using 455 x 106 B{bar B} pairs recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy ee− collider. The branching fractions are measured for the following ten decays: {bar B}° → D°p{bar p}, {bar B}° → D*°p{bar p}, {bar B}° → D+p{bar p}?−, {bar B}° → D*+p{bar p}?−, B− → D°p{bar p}?−, B− → D*°pp?−, {bar B}° → D°p{bar p}?−?+, {bar B}° → D*°p{bar p}?−?+, B− → D+p{bar p}?−?−, and B− → D*+p{bar p}?−?−. The four B− and the two five-body B° modes are observed for the first time. The four-body modes are enhanced compared to the three- and the five-body modes. In the three-body modes, the M(p{bar p}) and M(D{sup (*)0}p) invariant mass distributions show enhancements near threshold values. In the four-body mode {bar B}° → D+p{bar p}?−, the M(p?−) distribution shows a narrow structure of unknown origin near 1.5GeV/c2. The distributions for the five-body modes, in contrast to the others, are similar to the expectations from uniform phase-space predictions.

Author: Xuedong Chai
Publisher:
ISBN:
Category : B mesons
Languages : en
Pages : 340

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Author:
Publisher:
ISBN:
Category :
Languages : de
Pages :

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