Measurement of the $B^+\rightarrow P \bar{p} K^{+}$ Branching Fraction and Study of the Decay Dynamics


Book Description

With a sample of 232 x 106 [Upsilon](4S) 2!B{bar B} events collected with the BABAR detector, we study the decay B 2!p{bar p}K excluding charmonium decays to p{bar p}. We measure a branching fraction [Beta](B+ 2!p{bar p}K+) = (6.7 ± 0.5 ± 0.4) x 10−6. An enhancement at low p{bar p} mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate [Theta]*{sup ++} decaying into pK+ in the mass range 1.43 to 2.00 GeV/c2 and set limits on [Beta](B+ 2![Theta]*{sup ++} {bar p}) x [Beta]([Theta]*{sup ++} 2!pK+) at the 10−7 level.




MEASUREMENT OF THE BRANCHING FRACTIONS FOR THE DECAYS B°--]D*− P{bar P}?, B°--]D−p{bar P}?+, B0--]D*° P{bar P} AND B°--]D° P{bar P}


Book Description

The B° meson decay modes B° --> D*−p{bar p}?, D−p{bar p}+, {bar D}*°p{bar p}, and B° --> {bar D}°p{bar p} are studied in a sample of 124 x 106 B{bar B} pairs collected with the BABAR detector at the PEP-II collider. The decay of B° --> D−p{bar p}?+ is observed for the first time, with a measured branching fraction B(B° --> D−p{bar p}?+) = (3.80 ± 0.35 ± 0.46) x 10−4. The following branching fractions are also determined: B(B° --> D*−p{bar p}?+) = (5.61 ± 0.59 ± 0.73) x 10−4, B(B° --> {bar D}*° p{bar p}) = (0.67 ± 0.21 ± 0.09) x 10−4, and B(B° --> {bar D}°p{bar p}) = (1.24 ± 0.14 ± 0.12) x 10−4. In each decay mode the invariant mass spectra of the charmed mesons and the baryons are compared with a pure phase-space hypothesis in order to gain insight into the B meson decay dynamics. In particular, the Dalitz plots of {bar D}*°p versus {bar D}*°{bar p} for B° --> {bar D}*°p{bar p} and of {bar D}°p versus {bar D}°{bar p} for B° --> {bar D}°p{bar p} are presented. All results are preliminary.




MEASUREMENT OF THE BRANCHING FRACTIONS FOR THE DECAYS B[sup 0]--]D*[sup -] P[bar P][pi][sup +], B[sup 0]--]D[sup -]p[bar P][pi][sup +], B0--]D*[sup 0] P[bar P] AND B[sup 0]--]D[sup 0] P[bar P].


Book Description

The B[sup 0] meson decay modes B[sup 0] --> D*[sup -]p[bar p][pi][sup +], D[sup -]p[bar p][sup +], [bar D]*[sup 0]p[bar p], and B[sup 0] --> [bar D][sup 0]p[bar p] are studied in a sample of 124 x 10[sup 6] B[bar B] pairs collected with the BABAR detector at the PEP-II collider. The decay of B[sup 0] --> D[sup -]p[bar p][pi][sup +] is observed for the first time, with a measured branching fraction B(B[sup 0] --> D[sup -]p[bar p][pi][sup +]) = (3.80 [+-] 0.35 [+-] 0.46) x 10[sup -4]. The following branching fractions are also determined: B(B[sup 0] --> D*[sup -]p[bar p][pi][sup +]) = (5.61 [+-] 0.59 [+-] 0.73) x 10[sup -4], B(B[sup 0] --> [bar D]*[sup 0] p[bar p]) = (0.67 [+-] 0.21 [+-] 0.09) x 10[sup -4], and B(B[sup 0] --> [bar D][sup 0]p[bar p]) = (1.24 [+-] 0.14 [+-] 0.12) x 10[sup -4]. In each decay mode the invariant mass spectra of the charmed mesons and the baryons are compared with a pure phase-space hypothesis in order to gain insight into the B meson decay dynamics. In particular, the Dalitz plots of [bar D]*[sup 0]p versus [bar D]*[sup 0][bar p] for B[sup 0] --> [bar D]*[sup 0]p[bar p] and of [bar D][sup 0]p versus [bar D][sup 0][bar p] for B[sup 0] --> [bar D][sup 0]p[bar p] are presented. All results are preliminary.




Measurement of the Branching Fraction and Polarization for the Decay B[sup -][yields] D*[sup 0] K*[sup -].


Book Description

The authors present a study of the decay B[sup -][yields] D*[sup 0] K*[sup -] based on a sample of 86 million[Upsilon](4S)[yields] B[bar B] decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factor at SLAC. The authors measure the branching fraction[Beta](B[sup -][yields] D*[sup 0] K*[sup -])= (8.3[+-] 1.1(stat)[+-] 1.0(syst)) x 10[sup -4], and the fraction of longitudinal polarization in this decay to be[Lambda][sub L]/[Lambda]= 0.86[+-] 0.06(stat)[+-] 0.03(syst).




Measurement of the Branching Fraction of B{bar B} → K{sub S}°X Decay at the BABAR Experiment


Book Description

This thesis presents various studies of K{sub s}° mesons carried out at the BABAR experiment. Studying multiplicities of K{sub s}° in B{bar B} decays provides deeper knowledge of the detector performance and produces an important physical result. The branching fraction of B{bar B} → K{sub s}°X decay is measured using 286 pb−1 of data collected during the first year of physics running. The result obtained is BR(B{bar B} → XK{sub s}° →??−) = 0.216 ± 0.003(stat.) ± 0.015(syst.). Implications of this result to the presence of the new physics at TeV scale are discussed. The momentum spectrum of K{sub s}° coming from B{bar B} → XK{sub s}° →?+?− is also presented.




Measurement of the B0 -] Lambda-bar P Pi Branching Fraction AndStudy of the Decay Dynamics


Book Description

We present a measurement of the B{sup 0} {center_dot} {bar {Lambda}}p{pi}{sup -} branching fraction performed using the BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} collider. Based on a 232 million B{bar B} pairs data sample we measure: {center_dot} (B{sup 0} {center_dot} {bar {Lambda}}p{pi}{sup -}) = [3.30 {center_dot} 0.53(stat.) {center_dot} 0.31 (syst.)] {center_dot} 10{sup -6}. A measurement of the differential spectrum as a function of the di-baryon invariant mass m({Lambda}p) is also presented; this shows a near-threshold enhancement similar to that observed in other baryonic B decays.




Measurement of the Branching Fraction for B- --] D0 K*-


Book Description

The authors present a measurement of the branching fraction for the decay B− → D°K*− using a sample of approximately 86 million B{bar B} pairs collected by the BABAR detector from ee− collisions near the?(4S) resonance. The D° is detected through its decays to K−?+, K−?+?° and K−?+?−?+, and the K*− through its decay to K{sub S}°?−. They measure the branching fraction to be?(B− → D°K*−) = (6.3 ± 0.7(stat.) ± 0.5(syst.)) x 10−4.




Measurement of the Branching Fraction and Polarization for the Decay B− 2!D*° K*−


Book Description

The authors present a study of the decay B− → D*° K*− based on a sample of 86 million [Upsilon](4S) → B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factor at SLAC. The authors measure the branching fraction [Beta](B− → D*° K*−) = (8.3 ± 1.1(stat) ± 1.0(syst)) x 10−4, and the fraction of longitudinal polarization in this decay to be [Lambda]{sub L}/[Lambda] = 0.86 ± 0.06(stat) ± 0.03(syst).




Measurement of the Branching Fraction of B[bar B][yields] K[sub S][sup 0]X Decay at the BABAR Experiment


Book Description

This thesis presents various studies of K[sub s][sup 0] mesons carried out at the BABAR experiment. Studying multiplicities of K[sub s][sup 0] in B[bar B] decays provides deeper knowledge of the detector performance and produces an important physical result. The branching fraction of B[bar B][yields] K[sub s][sup 0]X decay is measured using 286 pb[sup -1] of data collected during the first year of physics running. The result obtained is BR(B[bar B][yields] XK[sub s][sup 0][yields][pi][sup+][pi][sup -])= 0.216[+-] 0.003(stat.)[+-] 0.015(syst.). Implications of this result to the presence of the new physics at TeV scale are discussed. The momentum spectrum of K[sub s][sup 0] coming from B[bar B][yields] XK[sub s][sup 0][yields][pi][sup+][pi][sup -] is also presented.




Branching Fraction Measurements of B --] Eta C K Decays


Book Description

We study the decays B 2![eta]{sub c}K and B° 2![eta]{sub c}K°, where the [eta]{sub c} is reconstructed in the K{sub S}° K{sup ±} [pi]{sup {-+}} and K+K− [pi]° decay modes. Results are based on a sample of 86 million B{bar B} pairs collected with the BABAR detector at the SLAC e+e− B Factory. We measure the branching fractions [Beta](B+ 2![eta]{sub c}K+) = (1.34 ± 0.09 ± 0.13 ± 0.41) x 10−3 and [Beta](B° 2![eta]{sub c}K°) = (1.18 ± 0.16 ± 0.13 ± 0.37) x 10−3, where the first error is statistical, the second is systematic, and the third reflects the [eta]{sub c} branching fraction uncertainty. In addition, we search for B 2![eta]{sub c}K events with [eta]{sub c} 2!2(K+K−) and [eta]{sub c} 2![phi][phi] and determine the [eta]{sub c} decay branching fraction ratios [Beta]([eta]{sub c} 2!2(K+K−))/[Beta]([eta]{sub c} 2!K{bar K}[pi]) = (2.3 ± 0.7 ± 0.6) x 10−2 and [Beta]([eta]{sub c} 2![phi][phi])/[Beta]([eta]{sub c} 2!K{bar K}[pi]) = (5.5 ± 1.4 {+-} 0.5) x 10−2.