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

Improved measurements of branching fractions for B -> K pi and B -> pi pi decays

We report improved measurements of branching fractions for B -> K pi and B -> pi pi decays based on a data sample of 449 million B Bbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+e^- collider. We also calculate the ratios of partial widths for the decays B -> K pi and pi pi, namely R_c = 1.08 +- 0.06 +- 0.08 and R_n = 1.08 +-0.08 +0.09-0.08, where the first and second errors are statistical and systematical, respectively. These ratios are sensitive to enhanced electroweak penguin contributions from new physics; the new measurements are, however, consistent with Standard Model expectations.Comment: 6 pages, 1 figur

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

Observation of B+->Lambda(+)(c)Lambda K--(c)+ and B-0 ->Lambda(+)(c)Lambda K--(c)0 decays

We report the first measurements of the doubly charmed baryonic B decays B ->Lambda(+)(c)Lambda K--(c). The B+->Lambda(+)(c)Lambda K--(c)+ decay is observed with a branching fraction of (6.5(-0.9)(+1.0)+/- 1.1 +/- 3.4)x10(-4) and a statistical significance of 15.4 sigma. The B-0 ->Lambda(+)(c)Lambda K--(c)0 decay is observed with a branching fraction of (7.9(-2.3)(+2.9)+/- 1.2 +/- 4.1)x10(-4) and a statistical significance of 6.6 sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of the Lambda(+)(c)-> pK(-)pi(+) decay branching fraction. The analysis is based on 357 fb(-1) of data accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider

Measurement of the wrong-sign decays D-0 -> K+pi(-)pi(0) and D-0 -> K+pi(-)pi(+)pi(-), and search for CP violation

Using 281 fb(-1) of data from the Belle experiment recorded at or near the Upsilon(4S) resonance, we have measured the rates of the "wrong-sign" decays D-0 -> K+pi(-)pi(0) and D-0 -> K+pi(-)pi(+)pi(-) relative to those of the Cabibbo-favored decays D-0 -> K-pi(+)pi(0) and D-0 -> K-pi(+)pi(+)pi(-). These wrong-sign decays proceed via a doubly Cabibbo-suppressed amplitude or via D-0-(D) over bar (0) mixing; the latter has not yet been observed. We obtain R-WS(K pi pi(0))=[0.229 +/- 0.015(stat)(-0.009)(+0.013)(syst)]% and R-WS(K3 pi)=[0.320 +/- 0.018(stat)(-0.013)(+0.018)(syst)]%. The CP asymmetries are measured to be -0.006 +/- 0.053 and -0.018 +/- 0.044 for the K+pi(-)pi(0) and K+pi(-)pi(+)pi(-) final states, respectively

Search for invisible decay of the Upsilon(1S)

We report results of a search for the invisible decay of the Upsilon(1S) via the Upsilon(3S)->pi(+)pi(-)Upsilon(1S) transition using a data sample of 2.9 fb(-1) at the Upsilon(3S) resonance. The data were collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. No signal is found, and an upper limit for the branching fraction at the 90% confidence level is determined to be B(Upsilon(1S)-> invisible)< 2.5x10(-3)

Improved constraints on D-0-(D)over-bar(0) mixing in D-0 -> K+ pi(-) decays from the Belle detector

We report the results of a search for D-0-D-0 mixing in D-0-> K(+)pi(-) decays based on 400 fb(-1) of data accumulated by the Belle detector at KEKB. Both assuming CP conservation and allowing for CP violation, we fit the decay-time distribution for the mixing parameters x(') and y('), as well as for the parameter R-D, the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays. The 95% confidence level region in the (x('2),y(')) plane is obtained using a frequentist method. Assuming CP conservation, we find x('2)< 0.72x10(-3) and -9.9x10(-3)< y(')< 6.8x10(-3) at the 95% confidence level; these are the most stringent constraints on the mixing parameters to date. The no-mixing point (0,0) has a confidence level of 3.9%. Assuming no mixing, we measure R-D=(0.377 +/- 0.008 +/- 0.005)%

Measurement of the branching fraction, polarization, and CP asymmetry for B-0 ->rho(+)rho(-) decays, and determination of the Cabibbo-Kobayashi-Maskawa phase phi(2)

We have measured the branching fraction B, longitudinal polarization fraction f(L), and CP asymmetry coefficients A and S for B-0->rho(+)rho(-) decays with the Belle detector at the KEKB e(+)e(-) collider using 253 fb(-1) of data. We obtain B=[22.8 +/- 3.8(stat)(-2.6)(+2.3)(syst)]x10(-6), f(L)=0.941(-0.040)(+0.034)(stat)+/- 0.030(syst), A=0.00 +/- 0.30(stat)+/- 0.09(syst), and S=0.08 +/- 0.41(stat)+/- 0.09(syst). These values are used to constrain the Cabibbo-Kobayashi-Maskawa phase phi(2); the solution consistent with the standard model is phi(2)=(88 +/- 17)degrees or 59 degrees <phi 2 < 115 degrees at 90% C.L

Measurement of the tau lepton mass and an upper limit on the mass difference between tau(+) and tau(-)

The mass of the tau lepton has been measured in the decay mode tau -> 3 pi nu(tau) using a pseudomass technique. The result obtained from 414 fb(-1) of data collected with the Belle detector is M-tau=[1776.61 +/- 0.13(stat)+/- 0.35(sys)] MeV/c(2). The upper limit on the relative mass difference between positive and negative tau leptons is |M-tau(+)-M-tau(-)|/M-tau < 2.8x10(-4) at 90% confidence level

Experimental constraints on the spin and parity of the Lambda(c)(2880)(+)

We report the results of several studies of the Lambda(+)(c)pi(+)pi X- final state in continuum e(+)e(-) annihilation data collected by the Belle detector. An analysis of angular distributions in Lambda(c)(2880)(+)->Sigma(c)(2455)(0,++)pi(+,-) decays strongly favors a Lambda(c)(2880)(+) spin assignment of 5/ over 3/2 or 1/2. We find evidence for Lambda(c)(2880)(+)->Sigma(c)(2520)(0,++)pi(+,-) decay and measure the ratio of Lambda(c)(2880)(+) partial widths Gamma(Sigma(c)(2520)pi)/Gamma(Sigma(c)(2455)pi)=0.225 +/- 0.062 +/- 0.025. This value favors the Lambda(c)(2880)(+) spin-parity assignment of 5/2(+) over 5/2(-). We also report the first observation of Lambda(c)(2940)(+)->Sigma(c)(2455)(0,++)pi(+,-) decay and measure Lambda(c)(2880)(+) and Lambda(c)(2940)(+) mass and width parameters. These studies are based on a 553 fb(-1) data sample collected at or near the Upsilon(4S) resonance at the KEKB collider