We present a search for the lepton flavor violating decay B+ --> K+ tau-/+ mu+/- using 383 million B Bbar events collected by the BABAR experiment. The branching fraction for this decay can be ...substantially enhanced in new physics models. The kinematics of the tau from the signal B decay are inferred from the K+, mu, and other B in the event, which is fully reconstructed in one of a variety of hadronic decay modes, allowing the signal B candidate to be fully reconstructed. We observe no excess of events over the expected background and set a limit of B(B+ --> K+ tau mu) < 7.7 x 10^-5 at 90% confidence level, where the branching fraction is for the sum of the K+ tau- mu+ and K+ tau+ mu- final states.
A search for the neutrinoless, lepton-flavor violating decay of the tau lepton into three charged leptons has been performed using 376 fb^{-1} of data collected at an e^+e^- center-of-mass energy ...around 10.58 GeV with the BaBar detector at the PEP-II storage rings. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (4-8) x 10^{-8} at 90% confidence level.
We study the time-dependent Dalitz plot of D->KSpi+pi- in B0->D(*)h0 decays, where h0 is a pi0, eta, eta', or omega meson and D*->Dpi0 using a data sample of 383 X 10^6 Upsilon(4S)->BBbar decays ...collected with the BABAR detector. We determine cos2beta = 0.42+-0.49+-0.09+-0.13, sin2beta = 0.29+-0.34+-0.03+-0.05, and |lambda| = 1.01+-0.08+-0.02, where the first error is statistical, the second is the experimental systematic uncertainty, and the third, where given, is the Dalitz model uncertainty. Assuming the world average value for sin2beta and |lambda|=1, cos2beta>0 is preferred over cos2beta<0 at 86% confidence level.
In preparation for the tenfold luminosity upgrade of the Large Hadron Collider (the HL-LHC) around 2020, three-dimensional (3D) silicon pixel sensors are being developed as a radiation-hard candidate ...to replace the planar ones currently being used in the CMS pixel detector. This study examines an early batch of FBK sensors (named ATLAS08) of three 3D pixel geometries: 1E, 2E, and 4E, which respectively contain one, two, and four readout electrodes for each pixel, passing completely through the bulk. We present electrical characteristics and beam test performance results for each detector before and after irradiation. The maximum fluence applied is 3.5×1015 n eq/cm2.
3D-FBK pixel sensors with CMS readout: First test results Obertino, M.; Solano, A.; Vilela Pereira, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Volume:
718
Journal Article
Peer reviewed
Silicon 3D detectors consist of an array of columnar electrodes of both doping types which penetrate entirely in the detector bulk, perpendicularly to the surface. They are emerging as one of the ...most promising technologies for innermost layers of tracking devices for the foreseen upgrades of the LHC. Until recently, properties of 3D sensors have been investigated mostly with ATLAS readout electronics. 3D pixel sensors compatible with the CMS readout were first fabricated at SINTEF (Oslo, Norway), and more recently at FBK (Trento, Italy) and CNM (Barcelona, Spain). Several sensors with different electrode configurations, bump-bonded with the CMS pixel PSI46 readout chip, were characterized in laboratory and tested at Fermilab with a proton beam of 120GeV/c. Preliminary results of the data analysis are presented.
The authors search for the neutrinoless, lepton-flavor-violating tau decays {tau}{sup -} {yields} {ell}{sup -}V{sup 0}, where {ell} is an electron or muon and V{sup 0} is a fector meson reconstructed ...as {phi} {yields} K{sup +}K{sup -}, {rho} {yields} {pi}{sup +}{pi}{sup -}, K* {yields} K{sup +}{pi}{sup -}, {bar K}* {yields} K{sup -}{pi}{sup +}. The analysis has been performed using 451 fb{sup -1} of data collected at an e{sup +}e{sup -} center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage rings. The number of events found in the data is compatible with the background expectation, and upper limits on the branching fractions are set in the range (2.6-19) x 10{sup -8} at the 90% confidence level.
Upgrade of Nuclotron power supply system Karpinskii, V. N.; Kondrat’ev, N. G.; Osipenkov, A. L. ...
Physics of particles and nuclei letters,
12/2010, Volume:
7, Issue:
7
Journal Article
Peer reviewed
One of the trends of Nuclotron development lies in modifying the power supply system and upgrading the energy evacuation system of structural magnets in order to provide reliable durable operation of ...the synchrotron at a dipole magnet field level of 2 T. This is necessary for Nuclotron operation as part of the injection chain of the heavy-ion NICA collider under design at JINR and for the current program of physical studies. The principles of construction and specific features of the existing system based on a separate power supply of structural dipole and quadrupole magnetic elements are considered. The main provisions of the upgrade of the power supply system, structural and schematic diagrams, control schemes, and energy evacuation switch schemes from superconducting elements are presented.
The decay width and mass of the D s 1 ( 2536 ) + meson are measured via the decay channel D + s 1 → D * + K 0 S using 385 fb − 1 of data recorded with the BABAR detector in the vicinity of the Υ ...( 4 S ) resonance at the PEP-II asymmetric-energy electron-positron collider. The result for the decay width is Γ ( D + s 1 ) = 0.92 ± 0.03 ( stat . ) ± 0.04 ( syst . ) MeV . For the mass, a value of m ( D + s 1 ) = 2535.08 ± 0.01 ( stat . ) ± 0.15 ( syst . ) MeV / c 2 is obtained. The mass difference between the D + s 1 and the D * + is measured to be m ( D + s 1 ) − m ( D * + ) = 524.83 ± 0.01 ( stat . ) ± 0.04 ( syst . ) MeV / c 2 , representing a significant improvement compared to the current world average. The unnatural spin-parity assignment for the D + s 1 meson is confirmed.
We present a search for the radiative leptonic decay B + → ℓ + ν ℓ γ , where ℓ = e , μ , using a data sample of 465 × 10 6 B ¯¯¯ B pairs collected by the BABAR experiment. In this analysis, we fully ...reconstruct the hadronic decay of one of the B mesons in Υ ( 4 S ) → B + B − decays, then search for evidence of B + → ℓ + ν ℓ γ in the rest of the event. We observe no significant evidence of signal decays and report model-independent branching fraction upper limits of B ( B + → e + ν e γ ) < 17 × 10 − 6 , B ( B + → μ + ν μ γ ) < 24 × 10 − 6 , and B ( B + → ℓ + ν ℓ γ ) < 15.6 × 10 − 6 ( ℓ = e or μ ), all at the 90% confidence level.
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