Time-integrated luminosity recorded by the BABAR detector at the PEP-II e+e- collider

This article is the Preprint version of the final published artcile which can be accessed at the link below.We describe a measurement of the time-integrated luminosity of the data collected by the BABAR experiment at the PEP-II asymmetric-energy e+e- collider at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and in a continuum region below each resonance. We measure the time-integrated luminosity by counting e+e-→e+e- and (for the ϒ(4S) only) e+e-→μ+μ- candidate events, allowing additional photons in the final state. We use data-corrected simulation to determine the cross-sections and reconstruction efficiencies for these processes, as well as the major backgrounds. Due to the large cross-sections of e+e-→e+e- and e+e-→μ+μ-, the statistical uncertainties of the measurement are substantially smaller than the systematic uncertainties. The dominant systematic uncertainties are due to observed differences between data and simulation, as well as uncertainties on the cross-sections. For data collected on the ϒ(3S) and ϒ(2S) resonances, an additional uncertainty arises due to ϒ→e+e-X background. For data collected off the ϒ resonances, we estimate an additional uncertainty due to time dependent efficiency variations, which can affect the short off-resonance runs. The relative uncertainties on the luminosities of the on-resonance (off-resonance) samples are 0.43% (0.43%) for the ϒ(4S), 0.58% (0.72%) for the ϒ(3S), and 0.68% (0.88%) for the ϒ(2S).This work is supported by the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat à l’Energie Atomique and Institut National de Physique Nucléaire et de Physiquedes Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, Ministerio de Ciencia e Innovación (Spain), and the Science and Technology Facilities Council (United Kingdom). Individuals have received support from the Marie-Curie IEF program (European Union) and the A.P. Sloan Foundation (USA)

Observation of the baryonic decay B \uaf 0 \u2192 \u39bc+ p \uaf K-K+

We report the observation of the baryonic decay B\uaf0\u2192\u39bc+p\uafK-K+ using a data sample of 471 7106 BB\uaf pairs produced in e+e- annihilations at s=10.58GeV. This data sample was recorded with the BABAR detector at the PEP-II storage ring at SLAC. We find B(B\uaf0\u2192\u39bc+p\uafK-K+)=(2.5\ub10.4(stat)\ub10.2(syst)\ub10.6B(\u39bc+)) 710-5, where the uncertainties are statistical, systematic, and due to the uncertainty of the \u39bc+\u2192pK-\u3c0+ branching fraction, respectively. The result has a significance corresponding to 5.0 standard deviations, including all uncertainties. For the resonant decay B\uaf0\u2192\u39bc+p\uaf\u3c6, we determine the upper limit B(B\uaf0\u2192\u39bc+p\uaf\u3c6)<1.2 710-5 at 90% confidence level

The BaBar detector: Upgrades, operation and performance

Contains fulltext : 121729.pdf (preprint version ) (Open Access

Search for a light Higgs resonance in radiative decays of the (1S) with a charm tag

A search is presented for the decay (1S)→γA0, A0→cc¯, where A0 is a candidate for the CP-odd Higgs boson of the next-to-minimal supersymmetric standard model. The search is based on data collected with the BABAR detector at the (2S) resonance. A sample of (1S) mesons is selected via the decay (2S)→π+π-(1S). The A0→cc¯ decay is identified through the reconstruction of hadronic D0, D+, and D∗(2010)+ meson decays. No significant signal is observed. The measured 90% confidence-level upper limits on the product branching fraction B((1S)→γA0)×B(A0→cc¯) range from 7.4×10-5 to 2.4×10-3 for A0 masses from 4.00 to 8.95GeV/c2 and 9.10 to 9.25GeV/c2, where the region between 8.95 and 9.10GeV/c2 is excluded because of background from (2S)→γχbJ(1P), χbJ(1P)→γ(1S) decays. © 2015 American Physical Society

Observation of (B)over-bar -> D-(*()) pi(+)pi(-)l(-)(nu)over-bar Decays in e(+)e(-) Collisions at the Upsilon(4S) Resonance

We report on measurements of the decays of B\uaf mesons into the semileptonic final states B\uaf\u2192D( 17)\u3c0+\u3c0-\u3bd\uaf, where D( 17) represents a D or D 17 meson and - is an electron or a muon. These measurements are based on 471 7106 BB\uaf pairs recorded with the BABAR detector at the SLAC asymmetric B factory PEP-II. We determine the branching fraction ratios R\u3c0+\u3c0-( 17)=B(B\uaf\u2192D( 17)\u3c0+\u3c0-\u3bd\uaf)/B(B\uaf\u2192D( 17)-\u3bd\uaf) using events in which the second B meson is fully reconstructed. We find R\u3c0+\u3c0-=0.067\ub10.010\ub10.008 and R\u3c0+\u3c0- 17=0.019\ub10.005\ub10.004, where the first uncertainty is statistical and the second is systematic. Based on these results and assuming isospin invariance, we estimate that B\uaf\u2192D( 17)\u3c0\u3c0-\u3bd\uaf decays, where \u3c0 denotes either a \u3c0\ub1 and \u3c00 meson, account for up to half the difference between the measured inclusive semileptonic branching fraction to charm hadrons and the corresponding sum of previously measured exclusive branching fractions

Collins asymmetries in inclusive charged KK and K pi pairs produced in e(+)e(-) annihilation

We present measurements of Collins asymmetries in the inclusive process e(+)e(-) -&gt; h(1)h(2)X, h(1)h(2) = KK, K pi, pi pi, at the center-of-mass energy of 10.6 GeV, using a data sample of 468 fb(-1) collected by the BABAR experiment at the PEP-II B factory at SLAC National Accelerator Center. Considering hadrons in opposite thrust hemispheres of hadronic events, we observe clear azimuthal asymmetries in the ratio of unlike sign to like sign, and unlike sign to all charged h(1)h(2) pairs, which increase with hadron energies. The K pi asymmetries are similar to those measured for the pi pi pairs, whereas those measured for high-energy KK pairs are, in general, larger