Moscow State University

About: Moscow State University is a education organization based out in Moscow, Russia. It is known for research contribution in the topics: Catalysis & Laser. The organization has 66747 authors who have published 123358 publications receiving 1753995 citations. The organization is also known as: MSU & Lomonosov Moscow State University.

Angular analysis of the B 0 → K *0 μ + μ − decay using 3 fb −1 of integrated luminosity

Abstract: An angular analysis of the B0 → K*0(→ K+π−)μ+μ− decay is presented. The dataset corresponds to an integrated luminosity of 3.0 fb−1 of pp collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine CP-averaged observables and CP asymmetries, taking account of possible contamination from decays with the K+π− system in an S-wave configuration. The angular observables and their correlations are reported in bins of q2, the invariant mass squared of the dimuon system. The observables are determined both from an unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for q2-dependent decay amplitudes in the region 1.1 < q2 < 6.0 GeV2/c4, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of CP-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions.[Figure not available: see fulltext.]

First Evidence for the Decay B-s(0) -> mu(+) mu(-)

Abstract: A search for the rare decays Bs->mu+mu- and B0->mu+mu- is performed using data collected in 2011 and 2012 with the LHCb experiment at the Large Hadron Collider. The data samples comprise 1.1 fb^-1 of proton-proton collisions at sqrt{s} = 8 TeV and 1.0 fb^-1 at sqrt{s}=7 TeV. We observe an excess of Bs -> mu+ mu- candidates with respect to the background expectation. The probability that the background could produce such an excess or larger is 5.3 x 10^-4 corresponding to a signal significance of 3.5 standard deviations. A maximum-likelihood fit gives a branching fraction of BR(Bs -> mu+ mu-) = (3.2^{+1.5}_{-1.2}) x 10^-9, where the statistical uncertainty is 95% of the total uncertainty. This result is in agreement with the Standard Model expectation. The observed number of B0 -> mu+ mu- candidates is consistent with the background expectation, giving an upper limit of BR(B0 -> mu+ mu-) < 9.4 x 10^-10 at 95% confidence level.

Temporal factors in mental work: Effects of interrupted activities

Abstract: Although interruptions are daily occurring events for most working people, little research has been done on the impacts of interruptions on workers and their performance. This study examines the e Vects of interruptions on task performance and its regulation, as well as on workers’ psychological and psychophysiological state. Two parallel experiments were carried out in the Netherlands and in Russia, using a common conceptual framework and overlapping designs. Employees with relevant work experience carried out realistic text editing tasks in a simulated o Yce environment, while the frequency and complexity of interruptions were experimentally manipulated. It was hypothesized that interruptions: (i) would cause a deterioration of performance; (ii) evoke strategies to partially compensate for this deterioration; (iii) aVect subjects’ emotions and well-being negatively; and (iv) raise the level of eVort and activation. It was also hypothesized that greater frequency and complexity of interruptions would enhance the expected e Vects. The hypotheses are only partially cone rmed. The results show that, contrary to what was expected, interruptions cause people to perform the main task faster while maintaining the level of quality. Participants develop strategies enabling them to deal e Vectively with the interruptions, while actually over-compensating the potential performance decline. Interruptions do have a negative impact on emotion and well-being, and lead to an increase of e Vort expenditure, although not to an increase in activation. Thus the improved performance is achieved at the expense of higher psychological costs. Greater complexity evoked more favourable responses among the Dutch participants and more unfavourable ones among the Russian participants. These diVerences are interpreted in terms of the participants’ professional background. The research demonstrates that the e Vects of interruptions reach beyond the execution of additional tasks and the change of work strategies. Interruptions appear to have an after-e Vect, ine uencing the workers’ subsequent readiness to perform. Detailed analysis of the activity in the interruption interval, focusing on