A Frey

In the late fall and early winter, The Johns Hopkins University HF radar at Goose Bay, Labrador, observes the effects of atmospheric gravity waves on radar transmissions that are obliquely reflected from the ionosphere and subsequently backscattered from the Earth's surface. The waves exist under a wide variety of geomagnetic conditions; how ever, they are particularly noticeable under quiet conditions (0 ≤ Kp ≤ 1 +). The clearest signatures of the waves are spatially localized ...

A search for stable and long-lived massive particles of electric charge |Q/e|=1 or fractional charges of 2/3, 4/3, and 5/3 is reported using data collected by the OPAL detector at LEP, at centre-of-mass energies from 130 to 209 GeV. These particles are assumed to be pair-produced in e+e− collisions and not to interact strongly. No evidence for the production of these particles was observed. Model-independent upper limits on the production cross-section between 0.005 and 0.028 pb have ...

Deep inelastic charged-current reactions have been studied ine+p ande−p collisions at a center of mass energy of about 300GeV in the kinematic regionQ2>200GeV2 andx>0.006 using the ZEUS detector at HERA. The integrated cross sections forQ2>200GeV2 are found to be ...

We report the results of a study of the exclusive semileptonic decays B-→π0ℓ-ν¯ℓ, B¯0→π+ℓ-ν¯ℓ, B-→ρ0ℓ-ν¯ℓ, B¯0→ρ+ℓ-ν¯ℓ and B-→ωℓ-ν¯ℓ, where ℓ represents an electron or a muon. The events are tagged by fully reconstructing a second B meson in the event in a hadronic decay mode. The measured branching fractions are B(B-→π0ℓ-ν¯ℓ)=(0.80±0.08±0.04)×10-4, B(B¯0→π+ℓ-ν¯ℓ)=(1.49±0.09±0.07)×10-4, B(B-→ρ0ℓ-ν¯ℓ)=(1.83±0.10±0.10)×10-4, B(B¯0→ρ+ℓ-ν¯ℓ)=(3.22±0.27±0.24)×10-4, and ...

The cross section for ee+ e- → π+ π- J/ψ between 3.8 and 5.5 GeV is measured with a 967  fb(-1) data sample collected by the Belle detector at or near the Υ(nS) (n = 1,2,…,5) resonances. The Y(4260) state is observed, and its resonance parameters are determined. In addition, an excess of π+ π- J/ψ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parametrization with properties that are consistent with the Y(4008) state that was previously reported by ...

Administration of the glucocorticoid dexamethasone to rats significantly stimulated the synthesis of ribosomal RNA by hepatic nuclei in vitro, as determined by hybridization to plasmid DNA containing the appropriate gene from X. laevis. This effect was also seen in rats in which RNA polymerase B had previously been blocked by the administration of alpha-amanitin. RNA synthesized in response to the hormone hybridized to both the 5' and 3' end of the gene for the precursor to ribosomal ...

Photoproduction events which have two or more jets have been studied in the Wγp range 135 GeV < Wγp < 280 GeV with the ZEUS detector at HERA. A class of events is observed with little hadronic activity between the jets. The jets are separated by pseudorapidity intervals (Δη) of up to four units and have transverse energies greater than 6 GeV. A gap is defined as the absence between the jets of particles with transverse energy greater than 300 MeV. The fraction of events containing a gap ...

We report measurements of the branching fractions and direct CP asymmetries (ACP) for B→Kπ, ππ and KK decays (but not π0π0) based on the final data sample of 772×106 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We set a 90% confidence-level upper limit for K+K- at 2.0×10-7; all other decays are observed with branching fractions ranging from 10-6 to 10-5. In the B0/B¯0→K±π∓ mode, we confirm Belle’s previously reported ...

BABAR, the detector for the SLAC PEP-II asymmetric e+e− B Factory operating at the ϒ(4S) resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons ...

A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at [Formula: see text], corresponding to an integrated luminosity of approximately 600 pb-1. Charged Higgs bosons are assumed to be pair-produced and to decay into [Formula: see text], τντ or AW±. No signal is observed. Model-independent limits on the charged Higgs-boson production cross section are ...

Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm. A cut on xγOBS, the fraction of the photon energy participating in the production of the two jets of highest transverse energy, is used to define cross sections sensitive to the parton distributions in the proton and in the photon. The dependence of the dijet cross sections on pseudorapidity has been measured for xγOBS ⩾ 0.75 and xγOBS < 0.75. The ...

We report a measurement of the branching fraction ratios R(D(*)) of B¯→D(*)τ-ν¯τ relative to B¯→D(*)ℓ-ν¯ℓ (where ℓ=e or μ) using the full Belle data sample of 772×106BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. The measured values are R(D)=0.375±0.064(stat)±0.026(syst) and R(D*)=0.293±0.038(stat)±0.015(syst). The analysis uses hadronic reconstruction of the tag-side B meson and purely leptonic τ decays. The results are ...

We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. ...

We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23x10(6) Upsilon(4S)-->BbarB decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events in which one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the ...

This paper describes a topological search for an invisibly decaying Higgs boson, H, produced via the Bjorken process (e+e-→HZ). The analysis is based on data recorded using the OPAL detector at LEP at centre-of-mass energies from 183 to 209 GeV corresponding to a total integrated luminosity of 629 pb-1. In the analysis only hadronic decays of the Z boson are considered. A scan over Higgs boson masses from 1 to 120 GeV and decay widths from 1 to 3000 GeV revealed no indication for a ...