158 research outputs found
N=4 mechanics, WDVV equations and roots
N=4 superconformal multi-particle quantum mechanics on the real line is
governed by two prepotentials, U and F, which obey a system of partial
differential equations linear in U and generalizing the
Witten-Dijkgraaf-Verlinde-Verlinde (WDVV) equation for F. Putting U=0 yields a
class of models (with zero central charge) which are encoded by the finite
Coxeter root systems. We extend these WDVV solutions F in two ways: the A_n
system is deformed n-parametrically to the edge set of a general orthocentric
n-simplex, and the BCF-type systems form one-parameter families. A
classification strategy is proposed. A nonzero central charge requires turning
on U in a given F background, which we show is outside of reach of the standard
root-system ansatz for indecomposable systems of more than three particles. In
the three-body case, however, this ansatz can be generalized to establish a
series of nontrivial models based on the dihedral groups I_2(p), which are
permutation symmetric if 3 divides p. We explicitly present their full
prepotentials.Comment: 1+25 pages; v2: major revision (more general analysis, new solutions,
additional references); v3: improvements in sects.5,8,9, refs. adde
ЭКСПОРТ ВЫСШЕГО ОБРАЗОВАНИЯ: СОСТОЯНИЕ И ПЕРСПЕКТИВЫ В МИРЕ И РОССИИ
Статья посвящена экспорту высшего образования, приобретающему все более важное значение в стратегиях социально-экономического развития в различных странах мира. Эксперты оценивают мировой рынок высшего образования в 150 млрд. долл. США. Россия в настоящее время занимает менее 1% этого рынка. Впервые предпринимается попытка оценить вклад иностранных студентов, обучающихся в РФ, в экономику страны. Для проведения расчетов были использованы данные по численности иностранных студентов в 2013/2014 учебном году, обучавшихся в российских вузах. Показано, что за рассматриваемый период иностранные студенты потратили в России примерно 25,4 млрд. руб. Даны рекомендации по первоочередным мерам по расширению российского экспорта высшего образования.
A study of the centrally produced baryon-antibaryon systems in pp interactions at 450 GeV/c
A study of the centrally produced ppbar, ppbarpi, ppbarpipi and lambda lambda
channels has been performed in pp collisions using an incident beam momentum of
450 GeV/c. No significant new structures are observed in the mass spectra,
however, important new information on the production dynamics is obtained. A
systematic study of the production properties of these systems has been
performed and it is found that these systems are not produced dominantly by
double Pomeron exchange.Comment: 13 pages, Latex, 4 Figure
A measurement of the branching fractions of the f1(1285) and f1(1420) produced in central pp interactions at 450 GeV/c
A study of the f1(1285) and f1(1420) produced in central pp interactions has
been performed. For the first time in a single experiment the branching
fractions of both mesons in all major decay modes have been determined. Both
the f1(1285) and f1(1420) are consistent with being produced by double Pomeron
exchange.Comment: 15 pages, Latex, 5 Figures, submitted to Physics Letters
A study of the centrally produced phiphi system in pp interactions at 450 GeV/c
The reaction pp to pfps(K+K-K+K-) in which the K+K-K+K- system is centrally
produced has been studied at 450 GeV/c. Phi phi production has been found to
dominate this reaction and is compatible with being produced by double Pomeron
exchange. An angular analysis of the phi phi system favours JPC = 2++ and its
dPT dependence is similar to that observed for glueball candidates.Comment: 11 pages, Latex, 4 Figure
- …