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

Angular distributions in the decay B -> K*l(+)l(-)

We use a sample of 384 million BBbar events collected with the Babar detector at the PEP-II e+e- collider to study angular distributions in the rare decays B -> K* l+l-, where l+l- is either e+e- or mu+mu-. For low dilepton invariant masses, m(l+l-)3.2$ GeV/c^2, we measure AFB=0.76 (+0.52,-0.32) +/- 0.07 FL=0.71 (+0.20,-0.22) +/- 0.04.We are grateful for the excellent luminosity and machine conditions provided by our PEP-II colleagues, and for the substantial dedicated effort from the computing organizations that support BABAR. The collaborating institutions wish to thank SLAC for its support and kind hospitality. This work is supported by DOE and NSF (USA), NSERC (Canada), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (The Netherlands), NFR (Norway), MES (Russia), MEC (Spain), and STFC (United Kingdom). Individuals have received support from the Marie Curie EIF (European Union) and the A. P. Sloan Foundation.Peer reviewe

The BaBar detector: Upgrades, operation and performance

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

The DIRC detector at Babar

A dedicated particle identification system based on the Detection of Internally Reflected Cherenkov (DIRC) light will be used in the BaBar detector. We provide an overview of the DIRC concept, design, and expected performance of the production device and a status report on its construction and commissioning. The DIRC is expected to be operating in the BaBar detector on beam line at the PEP-II B Factory in late spring 1999

Observation of B→D(*) π+π−ℓ−νbar Decays in e+e- Collisions at the Υ(4S) Resonance

We report on measurements of the decays of Bbar mesons into the semileptonic final states Bbar-->D(*)pi+pi-l-nubar, where D(*) represents a D or D* meson and l- is an electron or a muon. These measurements are based on 471x10^6 BBbar pairs recorded with the BABAR detector at the SLAC asymmetric B factory PEP-II. We determine the branching fraction ratios R_pi+pi-(*)=B(Bbar-->D(*)pi+pi-l-nubar)/B(Bbar-->D(*)l-nubar) using events in which the second B meson is fully reconstructed. We find Rpi+pi-=0.067±0.010±0.008 and Rpi+pi-=0.019±0.005±0.004, where the first uncertainty is statistical and the second is systematic. Based on these results and assuming isospin invariance, we estimate that Bbar-->D(*)pipil-nubar decays, where pi denotes either a pi± and pi0 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

Dalitz plot analyses of B-0 -> (D-DK+)-K-0 and B+-> (D)over-bar(-)D(0)K(+) decays

We present Dalitz plot analyses for the decays of B mesons to D−D0K+ and D¯0D0K+. We report the observation of the D∗s1(2700)+ resonance in these two channels and obtain measurements of the mass M(D∗s1(2700)+)=2699+14−7  MeV/c2 and of the width Γ(D∗s1(2700)+)=127+24−19  MeV, including statistical and systematic uncertainties. In addition, we observe an enhancement in the D0K+ invariant mass around 2350–2500  MeV/c2 in both decays B0→D−D0K+ and B+→D¯0D0K+, which we are not able to interpret. The results are based on 429  fb−1 of data containing 471×106BB¯ pairs collected at the ϒ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory

Dalitz plot analyses of B0→D−D0K+B^0 \to D^- D^0 K^+ and B+→D‾0D0K+B^+ \to \overline{D}^0 D^0 K^+ decays

See paper for full list of authors - 15 pages, 4 figures, submitted to Physical Review DInternational audienceWe present Dalitz plot analyses for the decays of B mesons to D−D0K+ and D¯¯¯0D0K+. We report the observation of the D∗s1(2700)+ resonance in these two channels and obtain measurements of the mass M(D∗s1(2700)+)=2699+14−7MeV/c2 and of the width Γ(D∗s1(2700)+)=127+24−19MeV, including statistical and systematic uncertainties. In addition, we observe an enhancement in the D0K+ invariant mass around 2350--2500 MeV/c2 in both decays B0→D−D0K+ and B+→D¯¯¯0D0K+, which we are not able to interpret. The results are based on 429 fb−1 of data containing 471×106BB¯¯¯ pairs collected at the Υ(4S) resonance with the BaBar detector at the SLAC National Accelerator Laboratory

Search for Long-Lived Particles in e(+)e(-) Collisions

We present a search for a neutral, long-lived particle L that is produced in e+e− collisions and decays at a significant distance from the e+e− interaction point into various flavor combinations of two oppositely charged tracks. The analysis uses an e+e− data sample with a luminosity of 489.1  fb−1 collected by the BABAR detector at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and just below the ϒ(4S). Fitting the two-track mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the L production cross section, branching fraction, and reconstruction efficiency for six possible two-body L decay modes as a function of the L mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction ℬ(B→XsL), where Xs is a strange hadronic system