The new closed form solutions of the (2+1)-dimensional Zabolotskaya–Khokhlov equation are constructed by using the similarity transformations method via Lie group theory. The Zabolotskaya–Khokhlov equation has been reduced into a new partial differential equation with smaller number of independent variables. Further using the similarity transformations method the new partial differential equati...

We consider the computation of D and B fragmentation functions in e+e− annihilation. We compare the results of fitting present data using the nextto-leading-logarithmic resummed approach, versus the O(αs) fixed-order calculation, including also mass-suppressed effects. We also propose a method for merging the fixed-order calculation with the resummed approach.

A probabilistic interpretation is constructed for the symmetry group G of the finite differencedifferential equation ∂tη(x, t) = η(x, t) − η(x+ 1, t) using the Doob transform for Markov (jump) processes. While the first three generators of G correspond to the identity and to space and time shifts, we show that in this interpretation the fourth generator of G is associated to time dilations and ...

so that the creation operator is separated from the annihilation one. Later, we will also need the concept of normal order ; so let us define the normal ordering symbol N() to place whatever operators in normal order, for example N ( a(p)a(k)†a(q) ) ≡ a(k)†a(p)a(q) . (4) The meaning of the “time–ordering” symbol T is well known: it instructs us to place the operators that follow in order with t...

A re-analysis of some pp and pn data, at rest and in flight, obtained in bubble chamber experiments, is presented. The (ππ) and (KSKS) final states for the channels (2ππ) and (KSKSπ) are investigated. Evidence for a narrow meson resonance structure, cautiously suggested as f0(1500), is given. In the (π π) invariant mass distribution from pn annihilations in flight, using the method of differenc...

Triangular norms (t-norms for short) play a crucial role in several fields of mathematics and AI. For an exhaustive overview on t-norms we refer to [20]. Recently an increasing interest of left-continuous t-norm based theories can be observed (see e.g. [3, 5, 6, 7, 18]). In this paper we discuss in detail the presently existing construction methods which result in left-continuous triangular nor...

We systematically investigate the exciton dynamics in monolayered, bilayered, and trilayered WS2 two-dimensional (2D) crystals by time-resolved photoluminescence (TRPL) spectroscopy. The exciton lifetime when free of exciton annihilation was determined to be 806 ± 37 ps, 401 ± 25 ps, and 332 ± 19 ps for WS2 monolayer, bilayer, and trilayer, respectively. By measuring the fluorescence quantum yi...

High-energy photons from pair annihilation of dark matter particles contribute to the cosmic gamma-ray background (CGB) observed in a wide energy range. The precise shape of the energy spectrum of CGB depends on the nature of dark matter particles. In order to discriminate between the signals from dark matter annihilation and other astrophysical sources, however, the information from the energy...