We search for evidence of a light scalar boson in the radiative decays of the Υ ( 2 S ) and Υ ( 3 S ) resonances: Υ ( 2 S , 3 S ) → γ A 0 , A 0 → μ + μ − . Such a particle appears in extensions of ...the standard model, where a light C P -odd Higgs boson naturally couples strongly to b quarks. We find no evidence for such processes in the mass range 0.212 ≤ m A 0 ≤ 9.3 GeV in the samples of 99 × 10 6 Υ ( 2 S ) and 122 × 10 6 Υ ( 3 S ) decays collected by the BABAR detector at the SLAC PEP-II B factory and set stringent upper limits on the effective coupling of the b quark to the A 0 . We also limit the dimuon branching fraction of the η b meson: B ( η b → μ + μ − ) < 0.9 % at 90% confidence level.
Charged-lepton flavor-violating processes are unobservable in the standard model, but they are predicted to be enhanced in several extensions to the standard model, including supersymmetry and models ...with leptoquarks or compositeness. We present a search for such processes in a sample of 99x10(6)Upsilon(2S) decays and 117x10(6)Upsilon(3S) decays collected with the BABAR detector. We place upper limits on the branching fractions B(Upsilon(nS)-->e(+/-)tau(-/+)) and B(Upsilon(nS)-->mu(+/-)tau(-/+)) (n=2,3) at the 10(-6) level and use these results to place lower limits of order 1 TeV on the mass scale of charged-lepton flavor-violating effective operators.
Search for the decay modes B ± → h ± τ ℓ Grauges, E.; Milanes, D. A.; Schroeder, T. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
07/2012, Letnik:
86, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present a search for the lepton flavor violating decay modes B+/- to h+/- tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472 million BBbar pairs. The search uses events ...where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the tau four-momentum. The resulting tau candidate mass is our main discriminant against combinatorial background. We see no evidence for B+/- to h+/- tau l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10^-5.
Background
There is paucity of information on rituximab-associated hypogammaglobulinemia (HGG) and its potential infectious consequences in children treated for idiopathic nephrotic syndrome (INS).
...Methods
A survey was distributed by the European Society Pediatric Nephrology to its members. It addressed the screening and management practices of pediatric nephrology units for recognizing and treating RTX-associated HGG and its morbidity and mortality. Eighty-four centers which had treated an overall 1328 INS children with RTX responded.
Results
The majority of centers administered several courses of RTX and continued concomitant immunosuppressive therapy. Sixty-five percent of centers routinely screened children for HGG prior to RTX infusion, 59% during, and 52% following RTX treatment. Forty-seven percent had observed HGG prior to RTX administration, 61% during and 47% >9 months following treatment in 121, 210, and 128 subjects respectively. Thirty-three severe infections were reported among the cohort of 1328 RTX-treated subjects, of whom 3 children died. HGG had been recognized in 30/33 (80%) of them.
Conclusions
HGG in steroid-dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS) children is probably multifactorial and can be observed prior to RTX administration in children with SDNS/FRNS. Persistent HGG lasting >9 months from RTX infusion is not uncommon and may increase the risk of severe infections in this cohort. We advocate for the obligatory screening for HGG in children with SDNS/FRNS prior to, during, and following RTX treatment. Further research is necessary to identify risk factors for developing both HGG and severe infections before recommendations are made for its optimal management.
Graphical abstract
A higher resolution version of the Graphical abstract is available as
Supplementary information
We report the results of a search for the bottomonium ground state η b ( 1 S ) in the photon energy spectrum with a sample of ( 109 ± 1 ) million of Υ ( 3 S ) recorded at the Υ ( 3 S ) energy with ...the BABAR detector at the PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at E γ = 921.2 + 2.1 − 2.8 ( stat ) ± 2.4 ( syst ) MeV with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition Υ ( 3 S ) → γ η b ( 1 S ) . This photon energy corresponds to an η b ( 1 S ) mass of 9388.9 + 3.1 − 2.3 ( stat ) ± 2.7 ( syst ) MeV / c 2 . The hyperfine Υ ( 1 S ) - η b ( 1 S ) mass splitting is 71.4 + 2.3 − 3.1 ( stat ) ± 2.7 ( syst ) MeV / c 2 . The branching fraction for this radiative Υ ( 3 S ) decay is estimated to be 4.8 ± 0.5 ( stat ) ± 1.2 ( syst ) × 10 − 4 .
We present a search for nine lepton-number-violating and three lepton-flavor-violating neutral charm decays of the type D0→h′−h−ℓ′+ℓ+ and D0→h′−h+ℓ′±ℓ∓, where h and h′ represent a K or π meson and ℓ ...and ℓ′ an electron or muon. The analysis is based on 468 fb−1 of e+e− annihilation data collected at or close to the ϒ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signal is observed for any of the twelve modes, and we establish 90% confidence level upper limits on the branching fractions in the range (1.0–30.6)×10−7. The limits are between 1 and 3 orders of magnitude more stringent than previous measurements.
Evidence for the decay X ( 3872 ) → J / ψ ω Poireau, V.; Hooberman, B.; Kerth, L. T. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
07/2010, Letnik:
82, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present a study of the decays B^{0,+} --> J/psi pi^+ pi^- pi^0 K^{0,+}, using 467 10^6 BBbar pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872) --> J/psi omega, ...with product branching fractions B(B^+ --> X(3872)K^+) B(X(3872) --> J/psi omega) =0.6\pm0.2\stat \pm 0.1\syst 10^{-5}, and B(B^0 --> X(3872)K^0) B(X(3872) --> J/psi omega) =0.6\pm0.3\stat \pm 0.1\syst 10^{-5}. A detailed study of the pi^+ pi^- pi^0 mass distribution from X(3872) decay favors a negative-parity assignment.
We report the observation of the rare charm decay D0→K−π+e+e−, based on 468 fb−1 of e+e− annihilation data collected at or close to the center-of-mass energy of the ϒ(4S) resonance with the BABAR ...detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675<m(e+e−)<0.875 GeV/c2 of the electron-positron pair to be B(D0→K−π+e+e−)=(4.0±0.5±0.2±0.1)×10−6, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty in the branching fraction of the decay D0→K−π+π+π− used as a normalization mode. The significance of the observation corresponds to 9.7 standard deviations including systematic uncertainties. This result is consistent with the recently reported D0→K−π+μ+μ− branching fraction, measured in the same invariant mass range, and with the value expected in the standard model. In a set of regions of m(e+e−), where long-distance effects are potentially small, we determine a 90% confidence level upper limit on the branching fraction B(D0→K−π+e+e−)<3.1×10−6.
The processes e+e−→KS0K±π∓π0 and e+e−→KS0K±π∓η are studied over a continuum of energies from threshold to 4 GeV with the initial-state photon radiation method. Using 454 fb−1 of data collected with ...the BABAR detector at the SLAC PEP-II storage ring, the first measurements of the cross sections for these processes are obtained. The intermediate resonance structures from K*0(Kπ)0, K*(892)±(Kπ)∓, and KS0K±ρ∓ are studied. The J/ψ is observed in all of these channels, and corresponding branching fractions are measured.
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