16158852
Age Dating of Globular Clusters Using UBV(RI) Main-sequence Photometry in the Two-color Diagram: Age of NGC 6397
I propose and apply a method for deriving ages of the metal-poor globular clusters (GCs) in a distance-independent way, which is based on age indicator related to the main sequence in the two-color diagrams with U-B index. Age of the metal-poor GC NGC 6397 has been estimated, using Yale isochrones of Demarque et al. (1996), to be close to 16 Gyr provided the cluster metallicity is near [Fe/H]=-2.0.
14358326
Oldmetal‐rich globular cluster populations: Peak color and peak metallicity trends with mass of host spheroids
We address the problem of the factors contributing to a peak color trend of old metal-rich globular cluster (MRGC) populations with mass of their hosts, early-type galaxies and spheroidal subsystems of spiral ones (spheroids). The colormass trend is often converted to a metallicity-mass trend under the assumption that age effects are small or negligible. While direct estimates of the ages of MRGC populations neither can rule out nor reliably support the populations' age trend, key data on timing of the formation of spheroids and other indirect evidence imply it in the sense: the more massive spheroid the older on average its MRGC population. We show that the contribution of an allowable age trend of the MRGC populations to their peak color trend can achieve up to ∼50% or so. In this event the comparable value of the color trend, ∼30%, is due to alpha-element ratio systematic variations of the order of Δ[α /Fe] ≈ 0.1 to 0.2 dex because of a correlation between the [α /Fe] ratios and age. Hence a systematic variation of exactly [Fe/H] ratios may turn out to be less significant among the contributors, and its range many times lower, i.e. of the order of Δ[Fe/H]∼0.1 or even none, than the corresponding range deduced by assuming no age trend. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
117714331
Spin Physics Program At IHEP-Protvino
A new single‐spin asymmetry AN measurement has been carried out at IHEP at 50 GeV. AN was found to be −(6.2±1.5)% in the polarized target fragmentation region at −0.6<xF<−0.25. The result proves that asymmetry does not depend on beam energy. A review of polarization results from Protvino as well as a proposal of the new experiment SPASCHARM are also presented.
120005126
The BTeV electromagnetic calorimeter
Abstract The electromagnetic calorimeter for a new Fermilab collider program named BTeV is based on lead tungstate scintillating crystals (PbWO 4 ). Various properties of crystals manufactured by Russian and Chinese companies were measured at the U70 accelerator in Protvino. A dedicated beam momentum tagging system was used to measure the energy and spatial resolution.
16654679
Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam.
The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.
5296680
Design and performance of LED calibration system prototype for the lead tungstate crystal calorimeter
A highly stable monitoring system based on blue and red light emitting diodes coupled to a distribution network comprised of optical fibers has been developed for an electromagnetic calorimeter that uses lead tungstate crystals readout with photomultiplier tubes. We report of the system prototype design and on the results of laboratory tests. Stability better than 0.1% (r.m.s.) has been achieved during one week of prototype operation.
197456903
Total cross-section measurements for muon-neutrino, anti-muon-neutrino interactions in 3-GeV - 30-GeV energy range with IHEP-JINR neutrino detector
The results of total cross section measurements for theν μ ,\(\bar \nu _\mu \) interactions with isoscalar target in the 3 – 30 GeV energy range have been presented. The data were obtained with the IHEP-JINR Neutrino Detector in the “natural” neutrino beams of the U-70 accelerator. Neutrino fluxes were obtained by averaging the spectra, based on the calculations with the use of the experimental data on secondary particle yields from the target and muon fluxes measurements in 9 gaps of the muon filter, as well as the spectra determined from quasi-elastic events and spectra defined by extrapolating differential distributiondσ/dy in the regiony=0. The significant deviation from the linear dependence forσ tot versus neutrino energy is determined in the energy range less than 15 GeV.