96104178
Development and operation of gas catchers to thermalize fusion–evaporation and fragmentation products
Abstract A new approach to the production of low energy radioactive beams involves the stopping of fast beams produced by fragmentation, in-flight fission or fusion–evaporation reaction into a large gas catcher where the reaction products are thermalized in high-purity helium and extracted as singly charged ions for post-acceleration. This removes the limitation present in standard ISOL technique for species that are difficult to extract from the target/ion source assembly. This approach has been implemented at Argonne since 1998 to inject fusion–evaporation products in an ion trap system. Via a series of improvements since then, we now reach efficiencies for these devices of close to 50% with delay times below 10 ms. In preparation for the RIA project, a larger device for stopping fragmentation products is in preparation. The basic principles behind these devices together with results obtained and experience gained operating these devices will be presented. Preparation for a test of the large gas cell at the full RIA energy at GSI will also be presented.
122751074
Production of single W bosons at LEP
We report on the observation of single W boson production in a data sample collected by the L3 detector at LEP2. The signal consists of large missing energy final states with a single energetic lepton or two hadronic jets. The cross-section is measured to be 0.61(-0.33)(+0.43) +/- 0.05 pb at the centre of mass energy root s = 172 GeV, consistent with the Standard Model expectation. From this measurement the following limits on the anomalous gamma WW gauge couplings are derived at 95% CL: -3.6 < Delta kappa gamma < 1.5 and -3.6 < lambda gamma < 3.6. (C) 1997 Published by Elsevier Science B.V.
14588649
Production of e, mu and tau pairs in untagged two-photon collisions at LEP
The two-photon collision reaction e+e- --> e+e-l+l- has been studied at root(s) ~ 91 GeV using the L3 detector at LEP for l = e, muon , tau. We have analysed untagged configurations where the two photons are quasi-real. Good agreement is found between our measurements and the order alpha**4 QED expectation.
122717574
Search for neutralinos in Z decays
Abstract We have searched for neutralinos produced via the reactions e + e − → χχ′ and e + e − → χ′χ′, where the next-to lightest neutralino, χ′, decays into the lightest neutralino, χ, and either a photon or a fermion pair. Based on 1.8 × 10 6 hadronic Z decays collected with the L3 detector at LEP, no signal has been observed. We present upper limits of a few times 10 −5 on the branching ratios Z → χχ′ and Z → χ′χ′. In the framework of the Minimial Supersymmetric Standard Model, we exclude a lightest χ with m χ less than 18 GeV, if either tan β > 2 or the gluino mass m ≈ g > 100 GeV.
18308235
Search for new particles in hadronic events with isolated photons
Abstract A search for the neutral Higgs boson in the processes e + e − → Z → H 0 γ → q q γ and e + e − → Z → Z ∗ H 0 → q q γγ has been performed using 2.8 million hadronic Z decays collected with the L3 detector at LEP from 1991 through 1994. No evidence for these processes has been observed. Upper limits at 95% confidence level for the corresponding cross sections have been set and the results have been compared with theoretical predictions beyond the Standard Model.
122052372
Angular multiplicity fluctuations in hadronic Z decays and comparison to QCD models and analytical calculations
Abstract Local multiplicity fluctuations in angular phase space intervals are studied using factorial moments measured in hadronic events at s ≃91.2 GeV , which were collected by the L3 detector at LEP. Parton shower Monte Carlo programs agree well with the data. On the other hand, first-order QCD calculations in the Double Leading Log Approximation and the Modified Leading Log Approximation are found to deviate significantly from the data.
17722290
Active galactic nuclei with double-peaked balmer lines: I. Black hole masses and eddington ratios
Using stellar population synthesis, we model the stellar contribution for a sample of 110 double- peaked broad- line active galactic nuclei ( AGNs) from the Sloan Digital Sky Survey ( SDSS). The stellar velocity dispersions (sigma(*)) are obtained for 52 double- peaked AGNs with obvious stellar absorption features, ranging from 106 to 284 km s(-1). We also use multicomponent profiles to fit O III lambda lambda 4959, 5007 and H beta emission lines. Using the well- established M-bh-sigma(*) relation, the black hole masses are calculated to range from 1.0 x 10(7) to 5.5 x 10(8) M circle dot, and the Eddington ratio from similar to 0.01 to similar to 1. Comparing these with the known R-BLR-L relation, we can find the factor f, which indicates the BLRs' geometry, inclination, and kinematics. We find that f deviates greatly from 0.75, suggesting the nonvirial dynamics of broad- line regions. The peak separation is mildly correlated with the Eddington ratio and SMBH mass with almost the same correlation coefficients. This implies that it will be difficult to detect obvious double- peaked AGNs with higher Eddington ratios. Using the monochromatic luminosity at 5100 8 to trace the bolometric luminosity, we find that external illumination of the accretion disk is needed to produce the observed strength of the H similar to emission line.
118460517
INTEGRAL observations of the gamma-ray binary 1FGL J1018.6-5856
The Fermi-LAT collaboration has recently reported that one of their detected sources, namely, 1FGL J1018.6-5856, is a new gamma-ray binary similar to LS 5039. This has prompted efforts to study its multi-frequency behavior. In this report, we present the results from 5.78-Ms INTEGRAL IBIS/ISGRI observations on the source 1FGL J1018.6-5856. 
By combining all the available INTEGRAL data, a detection is made at a significance level of 5.4 sigma in the 18-40 keV band, with an average intensity of 0.074 counts/s . However, we find that, there is non-statistical noise in the image that effectively reduces the significance to about 4 sigma and a significant part of the signal appears to be located in a 0.2-wide phase region, at phases 0.4-0.6 (where even the corrected significance amounts to 90% of the total signal found). Given the scarcity of counts, a variability is hinted at about 3 sigma at the hard X-rays, with an anti-correlation with the Fermi-LAT periodicity. Should this behavior be true, it would be similar to that found in LS 5039, and prompt observations with TeV telescopes at phases anti-correlated with the GeV maximum.
118485758
Unveiling the super-orbital modulation of LS I +61 303 in X-rays
We found evidence for the super-orbital modulation in the X-ray emission of LS I +61 303 from the longest monitoring date by the RXTE. The time evolution of the modulated fraction in the orbital light curves can be well fitted with a sinusoidal function having a super-orbital period of 1667 days. However, we have found a 281.8+/-44.6 day shift between the super-orbital variability found at radio frequencies and our X-ray data. We also find a super-orbital modulation in the maximum count rate of the orbital light curves, compatible with the former results, including the shift.
122307207
Isospin effect of fragmentation reactions induced by intermediate energy heavy ions and its disappearance
The fragments produced in the reaction of O-18 + Be-9 at 60 MevV/nucleon were measured experimentally. The isotopic distribution of the fragmentation reaction products was well reproduced by using a modified statistical abrasion-ablation model This model predicts that the fragment isotopic distribution at a fixed atomic number Z shifts towards the neutron rich side for the neutron-rich projectile. This isospin effect will decrease with decreasing the fragment atomic number Z and disappear when (Z(proj)-Z)/Z(proj) becomes larger than 0.5. It was shown that the disappearance of the isospin effect of fragmentation reaction is induced by the geometry effect in abrasion stage and the evaporation effect later.
118510624
Search for supersymmetry in events with a lepton, a photon, and large missing transverse energy in pp collisions at $ \sqrt {s} = 7 $ TeV
A search is performed for an excess of events, over the standard model expectations, with a photon, a lepton, and large missing transverse energy in pp collisions at $ \sqrt {s} = 7 $ TeV. Such events are expected in many new physics models, in particular a supersymmetric theory that is broken via a gauge-mediated mechanism, when the lightest charged and neutral gauginos are mass degenerate. The data sample used in this search corresponds to an integrated luminosity of 35 pb-1 collected with the CMS detector at the LHC. No evidence of such an excess above the standard model backgrounds, dominated by W production, is found. The results are presented as 95% confidence level upper limits on the cross section for a benchmark gauge-mediated scenario, and are then converted into exclusion limits on the squark, gluino, and wino masses.