210 research outputs found

    D0 Silicon Microstrip Tracker

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    The D0 Run II silicon microstrip tracker (SMT) has 3 square meters of Si area. There are 792,576 channels read out by 6192 SVXIIe chips on 912 read out modules. The SMT provides track and vertex reconstruction capabilities over the full pseudorapidity coverage of the D0 detector. The full detector has been running successfully since April 2002. This presentation covers the experience in commissioning and operating, the recent electronics upgrade which improved stability of the SMT and estimates of the radiation damage.Comment: 5 pages, 10 figures, Presented at IEEE NSS 2005, Puerto Ric

    B(s) Properties at the Tevatron

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    Recent results on B{sub s} properties obtained by the CDF and D0 collaborations collected at the Tevatron Collider in the period 2002-2006 were presented at the Hadron Collider Physics Symposium 2006 (Duke University, Durham). The measurements of B{sub s} mass and width differences are discussed in details. Prospects on measurements of CP violation in B{sub s} system are given

    Magnetoelectric doubling and mixing of electric and magnetic field frequencies in a layered multiferroic heterostructure

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    Nonlinear magnetoelectric effects in a disk-like heterostructure composed of a layer of amorphous ferromagnet (FeBSiC) mechanically coupled to a layer of piezoelectric ceramics (lead zirconate titanate) were studied both experimentally and theoretically. The structure was excited by alternating electrical and magnetic fields far from its acoustic resonance frequency. This induced changes in the magnetic induction within the heterostructure which were recorded using an electromagnetic coil. The experiments were performed for excitations with electric and magnetic fields up to 250 V/cm and 6 Oe, respectively, and bias permanent magnetic fields up to 60 Oe. For large excitation fields, a generation of the second harmonic and harmonics corresponding to the sum and difference frequencies were observed. The coefficient of the frequency doubling for the converse magnetoelectric effect and the coefficient of mixing of electrical and magnetic field frequencies were found to be 4.6∙10 −6 G cm 2/V 2 and ∼1∙10 −2 G cm/(Oe∙V), respectively. A simple theoretical model qualitatively describing the experimental findings was proposed. It was shown that the nonlinearity in the converse magnetoelectric effect arises due to the nonlinear dependence of magnetic induction in the ferromagnetic layer on mechanical stress. </p

    Nonlinear magnetoelectric effect in a ferromagnetic-piezoelectric layered structure induced by rotating magnetic field

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    The magnetoelectric (ME) effect induced by a rotating magnetic field, h, in the presence of a dc magnetic field, H 0, is investigated in a disk-shaped ferromagnetic FeBSiC - piezoelectric lead zirconate titanate bilayer structure. It is found that, due to the nonlinear field-dependence of magnetostriction λ(H) in the ferromagnetic layer, voltage harmonics are generated. These harmonics have a specific dependence of their amplitude and phase on H 0 and h, which is different from the case of excitation with a linearly polarized field. A theory is developed that describes characteristics of the ME effect for the cases of weak h ≪ H 0 and strong h ≫ H 0 excitation fields. The effect can be employed in designing highly sensitive sensors of permanent and alternating magnetic fields. </p

    Nonlinear magnetoelectric effect in a layered ferromagnetic-piezoelectric heterostructure excited by transverse magnetic field

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    The nonlinear magnetoelectric effect in a heterostructure containing layers of amorphous ferromagnet FeBSiC and piezoelectric lead zirconate titanate ceramics has been investigated. The heterostructure was subjected to permanent, H 0, and alternating, h, magnetic fields applied in the structure plane. In contrast to previous studies, the excitation field was directed perpendicular to the permanent field (h ? H 0). The generation of even voltage harmonics across the piezoelectric layer was observed for excitation fields in the range of 0-3 Oe. The dependence of the second harmonic amplitude on the permanent field strength was found to differ significantly from a similar dependence upon longitudinal excitation, h//H 0. A theory was developed, which describes the field dependence of voltage harmonic amplitudes for the magnetoelectric effect excited by a transverse magnetic field. </p

    Non-collider searches for stable massive particles

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    The theoretical motivation for exotic stable massive particles (SMPs) and the results of SMP searches at non-collider facilities are reviewed. SMPs are defined such that they would be sufficiently long-lived so as to still exist in the cosmos either as Big Bang relics or secondary collision products, and sufficiently massive to be beyond the reach of any conceivable accelerator-based experiment. The discovery of SMPs would address a number of important questions in modern physics, such as the origin and composition of dark matter in the Universe and the unification of the fundamental forces. This review outlines the scenarios predicting SMPs and the techniques used at non-collider experiments to look for SMPs, eg in cosmic rays and bound in matter. The limits so far obtained on the fluxes and matter densities of SMPs which possess various detection-relevant properties such as electric and magnetic charge are given

    Non-Fermi liquid behavior from two-dimensional antiferromagnetic fluctuations: a renormalization-group and large-N analysis

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    We analyze the Hertz-Moriya-Millis theory of an antiferromagnetic quantum critical point, in the marginal case of two dimensions (d=2,z=2). Up to next-to-leading order in the number of components (N) of the field, we find that logarithmic corrections do not lead to an enhancement of the Landau damping. This is in agreement with a renormalization-group analysis, for arbitrary N. Hence, the logarithmic effects are unable to account for the behavior reportedly observed in inelastic neutron scattering experiments on CeCu_{6-x}Au_x. We also examine the extended dynamical mean-field treatment (local approximation) of this theory, and find that only subdominant corrections to the Landau damping are obtained within this approximation, in contrast to recent claims.Comment: 15 pages, 8 figure

    Electric dipole moments and the search for new physics

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    Static electric dipole moments of nondegenerate systems probe mass scales for physics beyond the Standard Model well beyond those reached directly at high energy colliders. Discrimination between different physics models, however, requires complementary searches in atomic-molecular-and-optical, nuclear and particle physics. In this report, we discuss the current status and prospects in the near future for a compelling suite of such experiments, along with developments needed in the encompassing theoretical framework.Comment: Contribution to Snowmass 2021; updated with community edits and endorsement

    Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

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    The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of s=1.96\sqrt s =1.96 TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is AFBttˉ=0.128±0.025A_{\mathrm{FB}}^{t\bar{t}} = 0.128 \pm 0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions
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