121259675
PION AND KAON MULTIPLICITIES IN HEAVY QUARK JETS FROM E+E- ANNIHILATION AT 29 GEV
Abstract The multiplicities per event of π± and K± are measured separately for e+e- annihilation into c c , b b , and light quark pairs at Ecm=29 GeV. The K± multiplicity is higher for heavy quark events than for light quark events. The π± multiplicity and the π± scaled differential cross section at low x=Ebeam/Ebeam are found to be higher for b b events than for other events.
18317704
Measurement of Tau branching ratios
Using the data accumulated at LEP in 1989 and 1990 with the ALEPH detector, the inclusive and exclusive branching ratios of the τ lepton have been measured assuming lepton universality inZ0 decays. The inclusive branching fractions for the τ decay into one, three, and five charged particles have been determined to be (85.45±0.97)%, (14.35±0.48)%, and (0.10±0.05)%, respectively, in agreement with the world averages. New undetected decay modes are determined to have a branching fraction of less than 2.1% at 95% CL. The measured branching ratios for quasi-exclusive channels are slightly larger than, but consistent with the world averages, except for the modes τ→3 hadrons+vτ andτ→hadron+2π0vτ, which are significantly larger. These latter branching ratios have been found to be (9.5±0.7)% and (10.2±1.1)%, respectively. The sum of all the measured quasi-exclusive branching ratios is (100.4±1.8)%. A fully exclusive analysis of modes with neutral pions shows no evidence for new photonic decay modes with a branching fraction limit of 3.4% at 95% CL.
140089864
Critical current, electro-mechanical properties and specific heat of bronze Nb-3_Sn conductors
125293645
EXPERIMENTAL STUDY OF HEAVY CHARGED LEPTONS AT PETRA
123029043
Evidence of soft and collinear gluon emission ine+e− hadronic events
In the study of rapidity distributions of charged pions produced ine+e− annihilation at 29 GeV, we observe a significant dip in the rapidity distributions aty≈0 for events with low sphericity. A comparison of data with several QCD-based phenomenological models strongly suggests that this structure is related to the emission of multiple soft and/or collinear gluons.
120548922
EXPERIMENTAL LIMITS ON THE PRODUCTION OF EXCITED LEPTONS AND STABLE HEAVY-LEPTONS
The results are reported of a search for excited muons (..mu..*) and electrons (e*) and for a stable charged heavy lepton by measurements of the e/sup +/e/sup -/..--> mu../sup +/..mu../sup -/, ..mu../sup +/..mu../sup -/..gamma.., ..mu../sup +/..mu../sup -/..gamma gamma.., and ..gamma gamma.. final states. Excluded are large regions of the lambda (coupling constant), M (mass) planes for spin-(1/2) ..mu..* and e*, and a new stable charged heavy lepton with mass<14 GeV.
135660011
Hybrid photodiode tube
We report the first test results on a new breed of light detector based on a photocathode followed by a silicon diode working in the bombarding mode.
117426890
Age spread in galactic star forming region W3 Main
We present near-infrared JHKs imaging as well as K-band multi-object spectroscopy of the massive stellar content of W3 Main using LUCI at the LBT. We confirm 13 OB stars by their absorption line spectra in W3 Main and spectral types between O5V and B4V have been found. Three massive Young Stellar Objects are identified by their emission line spectra and near-infrared excess. From our spectrophotometric analysis of the massive stars and the nature of their surrounding HII regions we derive the evolutionary sequence of W3 Main and we find an age spread of 2–3 Myr.
118151450
Forward-backward Asymmetry and Differential Cross Section of Top Quark in Flavor Violating Z' model at $\mathscr{O}(\alpha_s^2 \alpha_X)$
In this paper, forward-backward asymmetry and differential cross section of top quark in flavor violating Z' model up to O(α 2 s α X ) at Tevatron are calculated. In order to account for the top observed large forward-backward asymmetry, the new coupling g X among Z' and quarks will be not much less than strong coupling constant g s . After including the new higher order correction, the differential cross section can fit the data better than those only including the leading contributions from Z', while the forward-backward asymmetry is still in agreement with the measurement.
17067286
Hard Photodisintegration of a Proton Pair
We present the first study of high energy photodisintegration of proton-pairs through the gamma + 3He -> p+p+n channel. Photon energies from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. An s^{-11} scaling of the cross section was observed, as predicted by the constituent counting rule. The onset of the scaling is at a higher energy and the cross section is significantly lower then for pn pair photodisintegration. For photon energies below the scaling region, the scaled cross section was found to present a strong energy-dependent structure not observed in deuteron photodisintegration.
122268272
HIERARCHY IN HOŘAVA-LIKE GRAVITY
We investigate a Hořava-like gravity model in (4+1)-dimensional space–time. Differing from the original one, we put a critical exponent z to the extra space dimension, which preserves the 4-dimensional diffeomorphism. Surprisingly, we obtain a mass hierarchy in a way completely different from the Randall–Sundrum model, we also obtain an exponential factor solution with the use of Ricci-like flow. More interesting relations with AdS5/CFT4 are further demonstrated. Since AdS/CFT is a realization of holography, we conclude that the Hořava-like gravity may be also a realization of holography.