Study of the Baryon-Antibaryon Low-Mass Enhancements in Charmless Three-body Baryonic B Decays

The angular distributions of the baryon-antibaryon low-mass enhancements seen in the charmless three-body baryonic B decays B+ -> p pbar K+, B0 -> p pbar Ks, and B0 -> p Lambdabar pi- are reported. A quark fragmentation interpretation is supported, while the gluonic resonance picture is disfavored. Searches for the Theta+ and Theta++ pentaquarks in the relevant decay modes and possible glueball states G with 2.2 GeV/c2 < M-ppbar < 2.4 GeV/c2 in the ppbar systems give null results. We set upper limits on the products of branching fractions, B(B0 -> Theta+ p)\times B(Theta+ -> p Ks) Theta++ pbar) \times B(Theta++ -> p K+) G K+) \times B(G -> p pbar) < 4.1 \times 10^{-7} at the 90% confidence level. The analysis is based on a 140 fb^{-1} data sample recorded on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.Comment: 14 pages, 13 figure files, update of hep-ex/0409010 for journal submisssio

Improved Measurements of Partial Rate Asymmetry in B -> h h Decays

We report improved measurements of the partial rate asymmetry (Acp) in B -> h h decays with 140fb^-1 of data collected with the Belle detector at the KEKB e+e- collider. Here h stands for a charged or neutral pion or kaon and in total five decay modes are included: K-+ pi+-, K0s pi-+, K-+ pi0, pi-+ pi0 and K0s pi0. The flavor of the last decay mode is determined from the accompanying B meson. Using a data sample 4.7 times larger than that of our previous measurement, we find Acp(K-+ pi+-) -0.088+-0.035+-0.013, 2.4 sigma from zero. Results for other decay modes are also presented.Comment: 9 pages, 1 figur

Search for CP violation in the decay B0->D*+-D-+

We report a search for CP-violating asymmetry in B0 -> D*+- D-+ decays. The analysis employs two methods of B0 reconstruction: full and partial. In the full reconstruction method all daughter particles of the B0 are required to be detected; the partial reconstruction technique requires a fully reconstructed D- and only a slow pion from the D*+ -> D0 pi_slow+ decay. From a fit to the distribution of the time interval corresponding to the distance between two B meson decay points we calculate the CP-violating parameters and find the significance of nonzero CP asymmetry to be 2.7 standard deviations.Comment: 4 pages, 3 figure

Studies of the Decay B+- -> D_CP K+-

We report studies of the decay B+- -> D_CP K+-, where D_CP denotes neutral D mesons that decay to CP eigenstates. The analysis is based on a 29.1/fb data sample of collected at the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+ e- storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes involving D_CP are determined to be B(B- -> D_1 K-)/B(B- -> D_1 pi-)=0.125 +- 0.036 +- 0.010 and B(B- -> D_2 K-)/B(B- -> D_2 pi-)=0.119 +- 0.028 +- 0.006, where indices 1 and 2 represent the CP=+1 and CP=-1 eigenstates of the D0 - anti D0 system, respectively. We also extract the partial rate asymmetries for B+- -> D_CP K+-, finding A_1 = 0.29 +- 0.26 +- 0.05 and A_2 = -0.22 +- 0.24 +- 0.04.Comment: 10 pages, 2 figures, submitted to Physical Review Letter

Combining motivational and volitional approaches to reducing excessive alcohol consumption in pre-drinkers: A theory-based intervention protocol

Background: Pre-drinking refers to the consumption of alcohol at home or a private residence prior to attending a subsequent social event. We present the study protocol of an online theory-based intervention to reduce pre-drinking and related harm in pre-drinking undergraduates, using behavior change techniques targeting the motivational and volitional phases of behaviour. Design: A fully randomized 2 (autonomy support: present vs. absent) x 2 (implementation intention: present vs. absent) between-participants design will be used to ascertain the effectiveness of the intervention in reducing pre-drinking alcohol consumption and alcohol-related harm. Participants will complete a range of theory-based measures prior to being allocated to one of the four experimental conditions. Four weeks later, participants will complete a follow-up questionnaire comprised of theoretical and behavioral measures. Analyses: The main and interactive effects of the intervention components in reducing our primary dependent variables, namely, pre-drinking alcohol consumption and alcohol-related harm at four-week follow-up will be tested. Baseline alcohol consumption and demographic information will be included in the analysis as covariates. Discussion: This online intervention is the first to be developed to reduce pre-drinking alcohol consumption, a behaviour linked to increased risk of alcohol-related harm. The intervention targets motivational and volitional components of the behaviour change process and is therefore likely to lead to greater reductions in pre-drinking alcohol consumption and experience of alcohol-related harm compared to either approach in isolation. If successful, the intervention can be implemented across various contexts and in populations where pre-drinking is prevalent. © 2016 Caudwell et al

Measurement of masses and branching ratios of Ξc+\Xi_c^+ and Ξc0\Xi_c^0 baryons

We report a measurement of the $\Xi_c^+$ and $\Xi_c^0$ baryon masses, and the branching ratios for various $\Xi_c$ decays, using $140 \mathrm{fb}^{-1}$ of data collected by the Belle experiment at the KEKB $e^+ e^-$ collider.The mass splitting $m_{\Xi_c^0} - m_{\Xi_c^+}$ is found to be $2.9\pm 0.5 \mathrm{MeV}/c^2$; this measurement is three times as precise as the current world average. We measure the branching ratios $\Gamma (\Xi_c^+\to \Lambda K\pi\pi)/\Gamma (\Xi_c^+\to\Xi\pi\pi) = 0.32\pm 0.03 \pm 0.02$ and $\Gamma (\Xi_c^0\to p KK\pi)/\Gamma (\Xi_c^0\to\Xi\pi) = 0.33\pm 0.03 \pm 0.03$, with improved precision, and measure $\Gamma (\Xi_c^+\to p K^0_S K^0_S)/\Gamma (\Xi_c^+\to\Xi\pi\pi) = 0.087\pm 0.016 \pm 0.014$, $\Gamma (\Xi_c^0\to \Lambda K\pi)/\Gamma (\Xi_c^0\to\Xi\pi) = 1.07\pm 0.12 \pm 0.07$ and $\Gamma (\Xi_c^0\to \Lambda K^0_S)/\Gamma (\Xi_c^0\to\Xi\pi) = 0.21\pm 0.02 \pm 0.02$ for the first time. In $\Xi_c^0$ decays to the $p K^- K^- \pi^+$ final state, we find evidence for the process $\Xi_c^0 \to p K^- \bar{K}{}^\ast(892)^0$ and measure the fraction of decays via this process to be $0.51\pm 0.03 \pm 0.01$.Comment: 16 pages, 9 figures, LaTeX, submitted to Phys. Lett.

Measurements of the branching fraction and polarization in B+->rho K-+(*0) decays

We present the results of a study of the charmless vector-vector decay B+->rho K-+(*0), based on 253 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We obtain the branching fraction B(B+->rho K-+(*0))=[8.9 +/- 1.7(stat)+/- 1.2(syst)]x10(-6). We also perform a helicity analysis of the rho and K-* vector mesons, and obtain the longitudinal polarization fraction f(L)(B+->rho K-+(*0))=0.43 +/- 0.11(stat)(-0.02)(+0.05)(syst)

Measurement of forward-backward asymmetry and wilson coefficients in B -> K(*)l(+)l(-)

We report the first measurement of the forward-backward asymmetry and the ratios of Wilson coefficients A(9)/A(7) and A(10)/A(7) in B -> K(*)l(+)l(-), where l represents an electron or a muon. We find evidence for the forward-backward asymmetry with a significance of 3.4 sigma. The results are obtained from a data sample containing 386x10(6) (B) over bar pairs that were collected on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider

Search for D-0-D-0(-) mixing in D-0 -> K+pi(-) decays and measurement of the doubly-Cabibbo-suppressed decay rate

We have searched for mixing in the Ddegrees-(D) over cap (0) D-0 system by measuring the decay-time distribution of D0 ! K(+)pi(-) decays. The analysis uses 90 fb(-1) of data collected by the Belle detector at the KEKB e(+) e(-) collider. We fit the decay-time distribution for the mixing parameters x(1) and y(1) and also for the parameter R-D, which is the ratio of the rate for the doubly-Cabibbo-suppressed decay D-0--> K(+)pi(-) to that for the Cabibbo-favored decay D-0 --> K- pi(+). We do these fits both assuming CP conservation and allowing for CP violation. We use a frequentist method to obtain a 95% C. L. region in the x(J2)- y(l) plane. Assuming no mixing, we measure R-D=(0: 381 +/- 0: 017 (+) (0.008)(-0.016))%

Measurements of B decays to two kaons

We report measurements of B meson decays to two kaons using 253 fb(-1) of data collected with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We find evidence for signals in B+->(K) over bar K-0(+) and B-0-> K-0(K) over bar (0) with significances of 3.0 sigma and 3.5 sigma, respectively. (Charge-conjugate modes are included.) The corresponding branching fractions are measured to be B(B+->(K) over bar K-0(+))=(1.0 +/- 0.4 +/- 0.1)x10(-6) and B(B-0-> K-0(K) over bar (0))=(0.8 +/- 0.3 +/- 0.1)x10(-6). These decay modes are examples of hadronic b -> d transitions. No signal is observed in the decay B-0-> K+K-, and we set an upper limit of 3.7x10(-7) at 90% confidence level