The TAIGA Collaboration Workshop takes place at DLNP on 5–8June2018. Representatives from Russian and German research centers participate in the workshop, discussing physical results obtained at the facility in 2015–2018, its current development status, and the nearest future prospects.An emphasis is placed on completing the fabrication of the second IACT-2gamma telescope at JINR, which is scheduled to be sent to Tunka this July.
The ATLAS collaboration published the results of searching for the associative production of a Higgs boson and a top–antitop quark pair
The ATLAS collaboration published the results of searching for the associative production of a Higgs boson and a top–antitop quark pair. Investigations were performed using the data collected in the channels of the Higgs boson decay into \(b\bar b\), WW∗, τ+τ−, γγ and ZZ∗over the entire LHC operation period. The production was observed with the statistical significance of 6.3 standard deviations at the expectation of 5.1 within the Standard Model. It is a pleasure to point out that DLNP scientists take an active part in this analysis, dealing with the channel of the Higgs boson decay into τ+τ−.
Direct interaction of the Higgs boson with the top quark is measured for the first time during a rare subatomic process
Yesterday, on 04 June 2018, two experiments, ATLAS and CMS, at the LHC, CERN, reported a discovery that relates two particles: the Higgs boson and the top quark.The scientists measured for the first time direct interaction of the Higgs boson with the top quark during a rare subatomic process.
The Higgs boson was predicted in the 1960s and observed in the CMS and ATLAS experiments in 2012 in collisions of LHC-generated protons by detecting particles into which is decays.The Higgs mechanism, which involves the Higgs boson, gives masses to elementary particles while leaving the photon massless.The Standard Model would be incomplete without the Higgs mechanism at LHC energies.Therefore, the t quark, most massive of quarks, must have the strongest relation to the Higgs boson.Production of a Higgs boson with a top–antitop quark pair (tt̄H) is a rare process, but it allows one to observe how these particles are related to each other.The top quark was observed in the CDF and DZero experiments at Fermilab’s Tevatron in 1995. Despite predictions of scientists about interaction of the top quark with the Higgs boson, all indications were, until now, below the threshold that allowed claiming a discovery. Now everything is quite different after the publications in Physical Review Letters and arXiv.org.
Today, at the Neutrino2018 conference in Heidelberg, the NOvA collaboration reported the first results from the antineutrino experiments, which indicate that muon antineutrinos oscillate into electron antineutrinos. This phenomenon is observed for the first time.
The NOvA neutrino experiment with a record large distance between the source and the detector is set in the Fermi National Accelerator Laboratory (Fermilab).The goal is to study neutrinos, the particles capable of passing through matter without any interaction with it.The long-term goal of the experiment is to find similarities and differences in how neutrinos and antineutrinos change from one type, muon neutrino in this case, to two other types, electron and tau neutrinos.The evidence for this transition of neutrinos and antineutrinos and their comparison will allow scientists to better understand how the Universe is constructed.
Manufacture of all parts for two professional inclinometers has been accomplished at the DLNP Workshop. The next stage is assembly and commissioning of the inclinometers at CERN. By the end of the year, the DLNP scientists will supply five of these new instruments to CERN and put them into operation. The work is carried out at the Department of Multiple Hadronic Processes under the leadership of Prof. J. Budagov within the JINR–CERN agreement and is aimed at stabilizing spatial positions of beams for increasing the LHC luminosity.
The high-precision instrument of the new generation, Precision Laser Inclinometer, makes it possible to monitor angular oscillations of the Earth in two orthogonal directions in the range of 10-6–4 Hz with a maximum sensitivity of 2.4∙10-11 rad/Hz1/2. It reliably detects angular inclinations of the Earth surface caused by the Moon, the Sun, distant (over 104 km away) earthquakes, the microseismic peak, and industrial sources.
Dmitri Semikoz (Directeur de Recherche CNRS, Paris) demonstrated that the standard static model of galactic cosmic rays suggested in 1990th came into conflict with a lot of modern experimental data, including variability measurements of the cosmic ray flux in the Galaxy, magnetic field measurements, and a great deal of anomalies in local observations of cosmic rays.