59 research outputs found
Registration of atmospheric neutrinos with the Baikal neutrino telescope
We present first neutrino induced events observed with a deep underwater
neutrino telescope. Data from 70 days effective life time of the BAIKAL
prototype telescope NT-96 have been analyzed with two different methods. With
the standard track reconstruction method, 9 clear upward muon candidates have
been identified, in good agreement with 8.7 events expected from Monte Carlo
calculations for atmospheric neutrinos. The second analysis is tailored to
muons coming from close to the opposite zenith. It yields 4 events, compared to
3.5 from Monte Carlo expectations. From this we derive a 90 % upper flux limit
of 1.1 * 10^-13 cm^-2 sec^-1 for muons in excess of those expected from
atmospheric neutrinos with zenith angle > 150 degrees and energy > 10GeV.Comment: 20 pages, 11 figure
The optical module of the Baikal deep underwater neutrino telescope
A deep underwater Cherenkov telescope has been operating since 1993 in stages
of growing size at 1.1 km depth in Lake Baikal. The key component of the
telescope is the Optical Module (OM) which houses the highly sensitive
phototube QUASAR-370. We describe design and parameters of the QUASAR-370, the
layout of the optical module, the front-end electronics and the calibration
procedures, and present selected results from the five-year operation
underwater. Also, future developments with respect to a telescope consisting
from several thousand OMs are discussed.Comment: 30 pages, 24 figure
Status of the Lake Baikal Experiment
We review the present status of the Baikal Underwater Neutrino Experiment and
report on neutrino events recorded with the detector stages NT-36 and NT-96.Comment: 5 pages, 4 PostScript figures, uses here.sty and mine.sty, submitted
to the Proc. of 5th Int. Workshop on Topics in Astroparticle and Underground
Physics (LNGS INFN, Assergi, September 7-11, 1997
The Lake Baikal neutrino experiment
We rewiew the present status of the Baikal Neutrino Project and present the
results of a search for high energy neutrinos with the detector intermediate
stage NT-96.Comment: 3 pages, 2 figures, to appear in the Proceedings of Sixth
International Workshop on Topics in Astroparticle and Underground Physics
(TAUP99), September 6-10, 1999, Pais, Franc
Warm Dark Matter from keVins
We propose a simple model for Warm Dark Matter (WDM) in which two fermions
are added to the Standard Model: (quasi-) stable "keVins" (keV inert fermions)
which account for WDM and their unstable brothers, the "GeVins" (GeV inert
fermions), both of which carry zero electric charge and lepton number, and are
(approximately) "inert", in the sense that their only interactions are via
suppressed couplings to the Z. We consider scenarios in which stable keVins are
thermally produced and their abundance is subsequently diluted by entropy
production from the decays of the heavier unstable GeVins. This mechanism could
be implemented in a wide variety of models, including E_6 inspired
supersymmetric models or models involving sterile neutrinos.Comment: 32 pages, 9 figures, 2 table
The Baikal Deep Underwater Neutrino Experiment: Results, Status, Future
We review the present status of the Baikal Underwater Neutrino Experiment and
present results obtained with the various stages of the stepwise increasing
detector: NT-36 (1993-95), NT-72 (1995-96) and NT-96 (1996-97). Results cover
atmospheric muons, first clear neutrino events, search for neutrinos from WIMP
annihilation in the center of the Earth, search for magnetic monopoles, and --
far from astroparticle physics -- limnology.Comment: Talk given at the Int. School on Nuclear Physics, Erice, Sept.199
Measurement of the top quark mass in the tt→ dilepton channel from √s = 8 TeV ATLAS data
The top quark mass is measured in the tt¯ → dilepton channel (lepton = e,μ) using ATLAS data recorded in the year 2012 at the LHC. The data were taken at a proton proton centre-of-mass energy of √s = 8 TeV and correspond to an integrated luminosity of about 20.2 fb−1. Exploiting the template method, and using the distribution of invariant masses of lepton–b-jet pairs, the top quark mass is measured to be mtop = 172.99±0.41 (stat) ±0.74 (syst) GeV, with a total uncertainty of 0.84 GeV. Finally, a combination with previous ATLAS mtop measurements from √s = 7 TeV data in the tt¯ → dilepton and tt¯ → lepton + jets channels results in mtop = 172.84±0.34 (stat)±0.61 (syst) GeV, with a total uncertainty of 0.70 GeV
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