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Title: Study of B Meson Decays to ppbarh Final States

Abstract

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 statesmore » 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}.« less

Authors:
;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
877963
Report Number(s):
SLAC-R-810
TRN: US200611%%151
DOE Contract Number:
AC02-76SF00515
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; ASYMMETRY; B MESONS; BARYONIUM; BARYONS; DALITZ PLOT; DECAY; DISTRIBUTION; FORM FACTORS; GLUEBALLS; MESONS; PROTONS; QUANTUM CHROMODYNAMICS; SHAPE; SPECTRA; Experiment-HEP,HEPEX

Citation Formats

Hryn'ova, Tetiana B., and /SLAC. Study of B Meson Decays to ppbarh Final States. United States: N. p., 2006. Web. doi:10.2172/877963.
Hryn'ova, Tetiana B., & /SLAC. Study of B Meson Decays to ppbarh Final States. United States. doi:10.2172/877963.
Hryn'ova, Tetiana B., and /SLAC. Wed . "Study of B Meson Decays to ppbarh Final States". United States. doi:10.2172/877963. https://www.osti.gov/servlets/purl/877963.
@article{osti_877963,
title = {Study of B Meson Decays to ppbarh Final States},
author = {Hryn'ova, Tetiana B. and /SLAC},
abstractNote = {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}.},
doi = {10.2172/877963},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 22 00:00:00 EST 2006},
month = {Wed Mar 22 00:00:00 EST 2006}
}

Technical Report:

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  • The authors present a search for B decays to charmless final states involving charged or neutral a{sub 0} mesons. The data sample corresponds to 89 million B{bar B} pairs collected with the BABAR detector operating at the PEP-II asymmetric-energy B Factory at SLAC. They find no significant signals and determine the following 90% C.L. upper limits: {Beta}(B{sup 0} {yields} a{sub 0}{sup -} {pi}{sup +}) < 5.1 x 10{sup -6}, {Beta}(B{sup 0} {yields} a{sub 0}{sup -}K{sup +}) < 2.1 x 10{sup -6} {Beta}(B{sup -} {yields} a{sub 0}{sup 0}{bar K}{sup 0}) < 3.9 x 10{sup -6}, {Beta}(B{sup +} {yields} a{sub 0}{sup 0}{pi}{supmore » +}) < 5.8 x 10{sup -6}, {Beta}(B{sup +} {yields} a{sub 0}{sup 0}K{sup +}) < 2.5 x 10{sup -6}, and {Beta}(B{sup 0} {yields} a{sub 0}{sup 0}K{sup 0}) < 7.8 x 10{sup -6}, where in all cases {Beta} indicates the product of branching fractions for B {yields} a{sub 0}X and a{sub 0} {yields} {eta}{pi}, where X indicates K or {pi}.« less
  • This thesis contains the results of an analysis of B{sup 0} {yields} {rho}{sup +}{rho}{sup -} using 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. From a fitted signal yield of 617 {+-} 52 events, the longitudinal polarizations fraction, f{sub L}, of the decay is measured to be 0.978 {+-} 0.014(stat){sub -0.029}{sup +0.021}(syst). The nearly fully longitudinal dominance of the B{sup 0} {yields} {rho}{sup +}{rho}{sup -} decay allows for a measurement of the time dependent CP parameters S{sub L} and C{sub L}, where the first parameter is sensitive tomore » mixing induced CP violation and the second one to direct CP violation. From the same signal yield, these values are found to be S{sub L} = -0.33 {+-} 0.24(stat){sub -0.14}{sup +0.08}(syst) and C{sub L} = - 0.03 {+-} 0.18(stat) {+-} 0.09(syst). The CKM angle {alpha} is then determined, using these results and the branching fractions and polarizations of the decays B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} and B{sup +} {yields} {rho}{sup +}{rho}{sup 0}. This measurement is done with an isospin analysis, in which a triangle is constructed from the isospin amplitudes of these three decay modes. A {chi}{sup 2} expression that includes the measured quantities expressed as the lengths of the sides of the isospin triangles is constructed and minimized to determine a confidence level on {alpha}. Selecting the solution compatible with the Standard Model, one obtains {alpha} = 100{sup o} {+-} 13{sup o}.« less
  • We present measurements of branching fractions and CP-violating asymmetries in B-meson decays to {rho}{sup +}{pi}{sup 0}, {rho}{sup 0}{pi}{sup +} and {rho}{sup 0}{pi}{sup 0}. The data sample comprises 89 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We find the charge-averaged branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{pi}{sup 0}) = (10.9 {+-} 1.9(stat) {+-} 1.9(syst)) x 10{sup -6} and {Beta}(B{sup 0} {yields} {rho}{sup 0}{pi}{sup +}) = (9.5 {+-} 1.1 {+-} 0.9) x 10{sup -6}, and we set a 90% confidence-level upper limit {Beta}(B{sup 0} {yields} {rho}{sup 0}{pi}{sup 0})more » < 2.9 x 10{sup -6}. We measure the charge asymmetries A{sub CP}{rho}{sup +}{pi}{sup 0} = 0.24 {+-} 0.16 {+-} 0.06 and {Alpha}{sub CP}{sup {rho}{sup 0}{pi}{sup +}} = -0.19 {+-} 0.11 {+-} 0.02. We also present the preliminary measurement of CP-violating asymmetries in B{sup 0} {yields} ({rho}{pi}){sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0} decays using a time-dependent Dalitz plot analysis. The results are obtained from a data sample of 213 million {Upsilon}(4S) {yields} B{bar B} decays, collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. This analysis extends the narrow-{rho} quasi-two-body approximation used in the previous analysis, by taking into account the interference between the {rho} resonances of the three charges. We measure 16 coefficients of the bilinear form factor terms occurring in the time-dependent decay rate of the B{sup 0} meson with the use of a maximum-likelihood fit. We derive the physically relevant quantities from these coefficients. We measure the direct CP-violation parameters {Alpha}{sub {rho}{pi}} = -0.088 {+-} 0.049 {+-} 0.013 and C = 0.34 {+-} 0.11 {+-} 0.05, where the first errors are statistical and the second systematic. For the mixing-induced CP-violation parameter we find S = -0.10 {+-} 0.14 {+-} 0.04, and for the dilution and strong phase shift parameters respectively, we obtain {Delta}C = 0.15 {+-} 0.11 {+-} 0.03 and {Delta}S = 0.22 {+-} 0.15 {+-} 0.03. For the angle {alpha} of the Unitarity Triangle we measure (113{sub -17}{sup +27} {+-} 6){sup o}; only a weak constraint is achieved at the significance level of more than two standard deviations. Finally, for the relative strong phase {delta}{sub +-} between the B{sup 0} {yields} {rho}{sup -}{pi}{sup +} and B{sup 0} {yields} {rho}{sup +}{pi}{sup -} transitions we find (-67{sub -31}{sup +28} {+-} 7){sup o}, with a similarly weak constraint at two standard deviations and beyond.« less
  • With a sample of 232x10{sup 6} {upsilon}(4S){yields}BB events collected with the BABAR detector, we study the decays of B mesons to pph final states, where h={pi}{sup +}, K{sub S}{sup 0}, K*{sup 0}, or K*{sup +}. We report evidence for the B{sup 0}{yields}ppK*{sup 0} decay, with a branching fraction (1.47{+-}0.45(stat){+-}0.40(syst))x10{sup -6}, and for the B{sup +}{yields}{eta}{sub c}K*{sup +} decay, with the branching fraction of B(B{sup +}{yields}{eta}{sub c}K*{sup +})xB({eta}{sub c}{yields}pp)=(1.57{sub -0.45}{sup +0.56}(stat){sub -0.3}={sub 6}{sup +0.46}(syst))x10{sup -6}, and provide improved measurements of the branching fractions of the other modes of this type. We also report the measurements of the charge asymmetry consistent withmore » zero in the B{sup +}{yields}pp{pi}{sup +}, B{sup 0}{yields}ppK*{sup 0}, and B{sup +}{yields}ppK*{sup +} modes. No evidence is found for the pentaquark candidate {theta}{sup +} in the mass range 1.52 to 1.55 GeV/c{sup 2}, decaying into pK{sub S}{sup 0}, or the glueball candidate f{sub J}(2220) in the mass range 2.2<m{sub pp}<2.4 GeV/c{sup 2}, and branching fraction limits are established for both at the 10{sup -7} level.« less