Measurement of the effective weak mixing angle $${\theta_{\textrm{eff}}}$$ in an experiment at the Super Charm Tau Factory is discussed for the case of a longitudinal polarization of electrons. A method for measuring the average electron beam polarization by means of analyzing the differential cross section for the decay process $${{J/\psi}}\to[\Lambda\to p\pi^{-}][{\bar{\Lambda}}\to{\bar{p}}\pi^{+}]$$ is proposed. At a collider luminosity of $$10^{35}\textrm{cm}^{-2}\textrm{s}^{-1}$$ and a polarization degree of $$0.8$$ , the parameter $${\sin^{2}{{\theta_{\textrm{eff}}}}}$$ can be measured to a relative precision better than $$1\%$$ , which will be sufficient for observing the deviation of $${\sin^{2}{{\theta_{\textrm{eff}}}}}$$ from its value at the $$Z$$ -boson peak.

The new coordinate-tracking detector based on drift chambers (CTUDC) is created in MEPhI. The detector represents two planes with total area of 30 m(2) placed on the opposite sides of Cherenkov water detector of 2000 m(3) volume. Each plane consists of 8 large multiwire drift chambers (4000x508x112 mm(3)). The key advantages of these chambers are a large effective area (1.85 m(2)) and a good coordinate and angular resolution with a small number of measuring channels. From the beginning of 2017, CTUDC operates as a part of the experimental complex NEVOD. The detector is designed for measuring of high density muon bundles (up to 10 particles per m2) at zenith angles in the range from 30 degrees to 90 degrees. The results of the CTUDC operation during the last year are given, the first distributions of the events in zenith angle, muon bundle multiplicity and density obtained from the detector data are discussed.

Results are presented from studying the anisotropy of the flux of very high-energy cosmic rays on the basis of muon bundles. Events were recorded in the period 2012–2018 by the DECOR coordinate-tracking detector, part of the unique research setup of the NEVOD experimental complex. The results from analyzing the anisotropy for two samples of events with muon bundles corresponding to different ranges of primary particle energy ( E > 10 15 eV and E > 10 16 eV) are discussed, and estimates are made of dipole anisotropy parameters (amplitude and phase).

The work is devoted to the study of the anisotropy of the high energy cosmic ray flux by means of muon bundles registered during 2012-2018 with the coordinate-tracking detector DECOR, which is a part of the Unique Scientific Facility «Experimental complex NEVOD». We have analyzed data for two event samples corresponding to E > 1015 eV and E > 1016 eV energy ranges of primary particles. The method of data processing is described and estimates of the dipole anisotropy parameters (the amplitude and the phase) are presented.

At the Unique Scientific Facility NEVOD (MEPhI), a large coordinate-tracking detector based on drift chambers for investigations of muon bundles generated by ultrahigh energy primary cosmic rays is being developed. One of the main characteristics of the bundle is muon multiplicity. Three methods of reconstruction of multiple events were investigated: the sequential search method, method of finding the straight line and method of histograms. The last method determines the number of tracks with the same zenith angle in the event. It is most suitable for the determination of muon multiplicity: because of a large distance to the point of generation of muons, their trajectories are quasiparallel. The paper presents results of application of three reconstruction methods to data from the experiment, and also first results of the detector operation.

First results of the analysis of cosmic ray anisotropy from muon bundles recorded in the coordinate tracking detector DECOR of the Experimental Complex NEVOD during the 2013–2017 measurement series are discussed. Two event samples differing in the multiplicity of muons, selection conditions, and ranges of the zenith and azimuth angles are analyzed. Estimates of the anisotropy parameters of the flux of primary cosmic rays with energies of 1015–1017 eV are presented.

Results of investigation of the high-energy cosmic-ray flux anisotropy using data on muon bundles are presented. The events were recorded in the period of 2013–2017 with the DECOR coordinate-tracking detector, which is a part of the unique scientific setup of the Experimental complex NEVOD. Methods for experimental data processing and taking atmospheric effects into account are described. Results of the analysis of two types of muon bundle events, which correspond to different ranges of primary particle energies (E > 1015 eV and E > 1016 eV) are discussed. Upper limits of the anisotropy amplitude for the two types of events are obtained.

The new coordinate-tracking detector based on drift chambers TREK, for research of ultrahighenergy cosmic rays is under development at National Research Nuclear University MEPhI. At the present, a prototype of the future detectorcoordinate-tracking unit based on drift chambers (CTUDC)is functioning. The prototype consists of 16 drift chambers. Results of experimental series have shown wide capabilities of this type of detectors for registration of muon bundles, including bundles with high density of particles. Results of operation of the prototype and prospects of developing a full-size detector TREK are presented.

The results of experiments of the last decades have shown that with the increase of energy of primary cosmic rays a clear excess of muon groups in comparison with the existing models of extensive air shower development (even assuming pure iron composition of PCR) appears. The problem is called 'muon puzzle' and it can be explained either by cosmo- or nuclear-physical reasons. One of the experiments in which the excess of muon groups was registered is a NEVODDECOR. The new large-scale coordinate- tracking detector of 254m(2) area based on drift chambers will increase the coverage of the side aperture of the Cherenkov water detector (CWD) NEVOD and significantly improve the resolution of close tracks. Multi-wire drift chambers TREK developed in IHEP for experiments at the neutrino channel of U-70 accelerator have large effective area (1.85m(2) ), a good coordinate and angular resolution with a small number of measuring channels. The first part of the detector named Coordinate-Tracking Unit based on the Drift Chambers (CTUDC) representing two coordinate planes of 8 drift chambers in each has been developed and mounted on the opposite sides of the CWD. It has the same principle of joint operation with NEVOD-DECOR triggering system so the main features of the TREK detector will be examined. Results of an examination of drift chambers at muon hodoscope URAGAN, a calibration of the CTUDC with DECOR and the first results of its joint operation with NEVOD triggering system are presented.

A coordinate tracking unit based on drift chambers (CTUDC) for registering single muons and muon bundles at large zenith angles is created at the MEPhI. The unit consists of multi-wire drift chambers (DCs) with large drift gaps. These DCs were used earlier for the neutrino channel on the U-70 accelerator. The CTUDC consists of two coordinate planes with 8 drift chambers in each, assembled on the opposite sides of the NEVOD Cherenkov water detector (CWD). The effective area of the unit is 29.6 m 2 . The CWD trigger system and DECOR coordinate-tracking detector provide timestamps for the drift chambers. The first results from the registration of single muons and muon bundles by the unit in combination with other detectors of the NEVOD experimental complex are presented.

The new coordinate-tracking unit on drift chambers (CTUDC) is launched in MEPhI. The detector is developed for joint operation with Cherenkov water detector (CWD) NEVOD of 2000 cubic meters and coordinate-tracking detector DECOR. It represents two coordinate planes of 8 large multi-wire drift chambers in each mounted on the opposite sides of CWD. The total area of the detector is about 30 square meters. The aim of the project is to examine the features of joint operation of such type detectors with NEVOD triggering system, accuracy and performance of drift chambers. This information will be used in development of a future large-scale detector TREK consisting of 264 same drift chambers. Results of cross-calibration of the CTUDC and coordinate-tracking detector DECOR, joint registration of high-multiplicity muon bundles with NEVOD-DECOR complex and performance of the new setup are presented.

We present the results of spectroscopic redshift measurements for the galaxy clusters from the first all-sky Planck catalogue that have been mostly identified based on the optical observations performed previously by our team (Planck Collaboration 2015a). Data on 13 galaxy clusters at redshifts from z ≈ 0.2 to z ≈ 0.8, including the improved identification and redshift measurement for the cluster PSZ1 G141.73+14.22 at z = 0.828, are provided. We have performed the measurements based on data from the Russian–Turkish 1.5-m telescope (RTT-150), the 2.2-m Calar Alto Observatory telescope, and the 6-m SAO RAS telescope (Bolshoy Teleskop Azimutalnyi, BTA).

We report a measurement of the branching fraction ratios R(D(*)) of Bbar -> D(*) tau- nubar_tau relative to Bbar -> D()* l- nubar_l (where l = e or mu) using the full Belle data sample of 772 x 10^6 BBbar pairs collected at the Y(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 tau decays. The results are consistent with earlier measurements and do not show a significant deviation from the standard model prediction.

We present a search for the rare leptonic decays B+→e+νe and B+→μ+νμ, using the full Υ(4S) data sample of 772×106 B¯B pairs collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. One of the B mesons from the Υ(4S)→B¯B decay is fully reconstructed in a hadronic mode, while the recoiling side is analyzed for the signal decay. We find no evidence of a signal in any of the decay modes. Upper limits of the corresponding branching fractions are determined as B(B+→e+νe)<3.5×10−6 and B(B+→μ+νμ)<2.7×10−6 at 90% confidence level.Received 25 June 2014DOI:https://doi.org/10.1103/PhysRevD.91.052016© 2015 American Physical Society

We report on the first observations of ¯B0→D1(2430)0ω, ¯B0→D1(2420)0ω, and ¯B0→D∗2(2460)0ω decays. The ¯B0→D*+ρ(1450)− decay is also observed. The branching fraction measurements are based on (771.6±10.6)×106 B¯B events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The fractions of longitudinal polarization of the D** states as well as partial wave fractions of the D1(2430)0 are obtained. We also set a 90% confidence level upper limit for the product of branching fractions of B(¯B0→D*+b1(1235)−)×B(b1(1235)−→ωπ−). The measurements show evidence of nontrivial final-state interaction phases for the ρ-meson-like amplitudes.6 MoreReceived 13 May 2015DOI:https://doi.org/10.1103/PhysRevD.92.012013© 2015 American Physical Society