174 research outputs found
Six loop analytical calculation of the field anomalous dimension and the critical exponent in -symmetric model
We report on a completely analytical calculation of the field anomalous
dimension and the critical exponent for the
-symmetric model at the record six loop level. We
successfully compare our result for with with the
predictions based on the method of the Borel resummation combined with a
conformal mapping. Predictions for seven loop contribution to the field
anomalous dimensions are given.Comment: 16 page
Measurements of integral muon intensity at large zenith angles
High-statistics data on near-horizontal muons collected with Russian-Italian
coordinate detector DECOR are analyzed. Precise measurements of muon angular
distributions in zenith angle interval from 60 to 90 degrees have been
performed. In total, more than 20 million muons are selected. Dependences of
the absolute integral muon intensity on zenith angle for several threshold
energies ranging from 1.7 GeV to 7.2 GeV are derived. Results for this region
of zenith angles and threshold energies have been obtained for the first time.
The dependence of integral intensity on zenith angle and threshold energy is
well fitted by a simple analytical formula.Comment: 4 pages, 4 figures, 1 tabl
Calibration of the NEVOD-EAS array for detection of extensive air showers
In this paper we discuss the calibration of the NEVOD-EAS array which is a
part of the Experimental Complex NEVOD, as well as the results of studying the
response features of its scintillation detectors. We present the results of the
detectors energy calibration, performed by comparing their response to
different types of particles obtained experimentally and simulated with the
Geant4 software package, as well as of the measurements of their timing
resolution. We also discuss the results of studies of the light collection
non-uniformity of the NEVOD-EAS detectors and of the accuracy of air-shower
arrival direction reconstruction, which have been performed using other
facilities of the Experimental Complex NEVOD: the muon hodoscope URAGAN and the
coordinate-tracking detector DECOR.Comment: 16 pages, 17 figures, To be submitted to Nuclear Instruments and
Methods
Tunka Advanced Instrument for cosmic rays and Gamma Astronomy
The paper is a script of a lecture given at the ISAPP-Baikal summer school in
2018. The lecture gives an overview of the Tunka Advanced Instrument for cosmic
rays and Gamma Astronomy (TAIGA) facility including historical introduction,
description of existing and future setups, and outreach and open data
activities.Comment: Lectures given at the ISAPP-Baikal Summer School 2018: Exploring the
Universe through multiple messengers, 12-21 July 2018, Bol'shie Koty, Russi
Local anisotropy of muon flux during Forbush decreases from URAGAN data
The approach to the analysis of spatial-angular characteristics of the muon flux variations at different phases of Forbush decrease development according to the muon snapshots (muongraphies) obtained using muon hodoscope URAGAN, as well as the analysis results are presented
Temperature effect corrections for URAGAN based on CAO, GDAS, NOAA data
For the analysis of muon flux variations caused by extra-atmospheric processes it is necessary to introduce corrections for meteorological effects. For temperature effect (TE) correction it is necessary to know the temperature profile of the atmosphere. As a rule, this profile is measured by meteorological balloons two or four times a day. Alternative sources are satellite observations and data obtained from models of atmosphere used for weather forecasting. Vertical temperature profiles obtained from NOAA satellites, GDAS (Global Data Assimilation System) and CAO data (Central Aerological Observatory, Russia) for standard isobaric levels were compared. Mean value of temperature difference for most levels does not exceed 1 K. Comparison of URAGAN data corrected for TE with CAO information, satellites and GDAS shows a good agreement. Counting rate and anisotropy of the muon flux corrected for meteorological effects for 2007-2014 are presented
Looking through the QCD conformal window with perturbation theory
We study the conformal window of QCD using perturbation theory, starting from the perturbative upper edge and going down as much as we can towards the strongly coupled regime. We do so by exploiting the available five-loop
computation of the -function and employing Borel resummation techniques both for the ordinary perturbative series and for the Banks-Zaks conformal expansion. Large- results are also used. We argue that the perturbative series for the -function is most likely asymptotic and non-Borel resummable, yet Borel resummation techniques allow to improve on ordinary perturbation theory. We find
substantial evidence that QCD with flavours flows in the IR to a conformal field theory. Though the evidence is weaker, we find indications that also might sit within the conformal window. We also compute the value
of the mass anomalous dimension at the fixed point and compare it with the available lattice results. The conformal window might extend for lower values of , but our methods break down for n_f<11, where we expect that non-perturbative effects become important. A similar analysis is performed in the Veneziano limit
Local anisotropy of muon flux during Forbush decreases from URAGAN data
The approach to the analysis of spatial-angular characteristics of the muon flux variations at different phases of Forbush decrease development according to the muon snapshots (muongraphies) obtained using muon hodoscope URAGAN, as well as the analysis results are presented
The precision of the IACT mechanical mounts of the TAIGA observatory
The TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) observatory is located in the Tunka valley (~50 km west from the southern shore of Lake Baikal) at an altitude of 675m a.s.l. The TAIGA observatory aims to address gamma-ray astronomy at energies from a few TeV to several PeV and CR physics from 100 TeV to several EeV. Its main feature is the complementary, hybrid approach to distinguish CR events from those of gamma rays. Currently TAIGA consists of ~80 wide-angle air Cherenkov detectors (HiSCORE stations), three ~4m diameter IACTs and several hundred surface and underground muon detectors, grouped in three jointly operating arrays. The exceptional feature of the TAIGA IACT array is it’s topology that allows one to aim for the optimal cost/performance by scanning the optimal inter-telescope distances from 300m up to 600m. The IACTs have alt-azimuth type mounts and 576-pixel imaging cameras in the foci, covering 9.6° aperture in the sky. The segmented reflectors of ~10m² area follow the Davis-Cotton design. The largest diameter of the hexagonal shape reflector is 4.3m and the focal length is 4.75m. The rigid telescope mount provides a maximum displacement of EAS image below 2mm (i.e. ≤ 0.024°) in the photodetector plane. The main parameters of IACTs are of a crucial importance for their efficient operation and is presented
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