U. Bitenc

Boosted objects: a probe of beyond the standard model physics

We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.

Measurement of the time-dependent CP-violating asymmetry in BO→KSOπOγ decays

We present a new measurement of CP-violation parameters in B(0)-->K(0)(S)pi(0)gamma decay based on a sample of 275 x 10(6) BB pairs collected at the Gamma(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. One of the B mesons is fully reconstructed in the B(0)-->K(0)(S)pi(0)gamma decay. The flavor of the accompanying B meson is identified from its decay products. CP-violation parameters are obtained from the asymmetry in the distribution of the proper time intervals between the two B decays. We obtain SK(0)(S)(pi(0)gamma) = -0.58(+0.46)(-0.38)(stat) +/- 0.11(syst) and AK(0)(S)(pi(0)gamma) = +0.03 +/- 0.34(stat) +/- 0.11(syst), for the K(0)(S)pi(0) invariant mass covering the full range up to 1.8 GeV/c2. We also measure the CP-violation parameters for the case B(0)-->K(*0)(-->K(0)(S)pi(0))gamma and obtain S(K(*0)gamma) = -0.79(+0.63)(-0.50)(stat) +/- 0.10(syst) for A(K(*0)gamma) fixed at 0.

Observation of B^+ ¿ ¿K^+

We report the first observation of the charmless hyperonic B decay, B+-->LambdaLambdaK+, using a 140 fb(-1) data sample recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB (e+)(e-) collider. The measured branching fraction is B(B+-->LambdaLambdaK+) = (2.91(+0.90)(-0.70) +/- 0.38) x 10(-6). We also perform a search for the related decay mode B+-->LambdaLambdapi+, but do not find a significant signal. We set a 90% confidence-level upper limit of B(B+-->LambdaLambdapi+) < 2.8 x 10(-6).

Measurement of polarization and triple-product correlations in B→K* decays

We present a measurement of the decay amplitudes and triple-product correlations in B ->phi K^* decays based on 140 fb^-1 of data recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+ e^- storage ring. The decay amplitudes for the different phi K^* helicity states are measured from the angular distributions of final state particles in the transversity basis. The longitudinal and transverse complex amplitude moduli and angles are |A_0|^2 = 0.51 +- 0.06 +- 0.04, |A_perp|^2 = 0.24 +- 0.06 +- 0.03, arg(A_parallel) = -2.21 +- 0.22 +- 0.05 rad, and arg(A_perp) = 0.72 +- 0.21 +- 0.06 rad. The T-violating asymmetries through triple-product correlations are measured to be consistent with zero.

Observation of the D1(2420)→Dπ+π- decays

We report on the first observation of D{sub 1}{sup 0}(2420){yields}D{sup 0}{pi}{sup -}{pi}{sup +} and D{sub 1}{sup +}(2420){yields}D{sup +}{pi}{sup -}{pi}{sup +} decays (where the contribution from the dominant known D{sub 1}{yields}D*{pi} decay mode is excluded) in the B{sup -}{yields}D{sub 1}{sup 0}{pi}{sup -} and B{sup 0}{yields}D{sub 1}{sup +}{pi}{sup -} decays, respectively. The observation is based on 15.2x10{sup 7} BB events collected with the Belle detector at the KEKB collider. We also set 90% confidence level upper limits for the branching fractions of the four following decays: B{sup -}{yields}D{sub 1}{sup 0}{pi}{sup -}, D{sub 1}{sup 0}{yields}D*{sup 0}{pi}{sup -}{pi}{sup +}, B{sup 0}{yields}D{sub 1}{sup +}{pi}{sup -}, D{sub 1}{sup +}{yields}D{sup *+}{pi}{sup -}{pi}{sup +}, B{sup -}{yields}D{sub 2}*{sup 0}(2460){pi}{sup -}, D{sub 2}*{sup 0}{yields}D*{sup 0}{pi}{sup -}{pi}{sup +}, B{sup 0}{yields}D{sub 2}*{sup +}(2460){pi}{sup -}, D{sub 2}*{sup +}{yields}D{sup *+}{pi}{sup -}{pi}{sup +}.We report on the first observation of

Determination of /Vub/ from measurements of the inclusive charmless semileptonic partial rates of B mesons using full reconstruction tags.

D_1\to D\pi^+\pi^-

Measurement of γγ → pp̄ production at Belle

decays (where the contribution from the dominant known

Observation of B0→π0π0

D_1 \to D^* \pi

Study of B-+/--> DCPK +/- and (DCPK +/-)-K-* decays

decay mode is excluded) in the

Study of decay mechanisms in B-->Lambda(+)(c)p pi(-) decays and observation of low-mass structure in the Lambda(+)(c)p system

B\to D_1\pi