New Travelling Wave Solutions of Two Nonlinear Physical Models by Using a Modified Tanh-Coth Method

In this work, a modified tanh – coth method is used to derive travelling wave solutions for (2 + 1)-dimensional Zakharov-Kuznetsov (ZK) equation and (3 + 1)-dimensional Burgers equation. A new variable is used to solve these equations and established new travelling wave solutions. </jats:p

Threat Rejection Fuels Political Dehumanization

Americans disagree about many things, including what threats are most pressing. We suggest people morally condemn and dehumanize opponents when they are perceived as rejecting the existence or severity of important perceived threats. We explore perceived "threat rejection" across five studies (N = 2,404) both in the real-world COVID-19 pandemic and in novel contexts. Americans morally condemned and dehumanized policy opponents when they seemed to reject realistic group threats (e.g., threat to the physical health or resources of the group). Believing opponents rejected symbolic group threats (e.g., to collective identity) was not reliably linked to condemnation and dehumanization. Importantly, the political dehumanization caused by perceived threat rejection can be soothed with a "threat acknowledgement" intervention

Invariant Measures and Decay of Correlations for a Class of Ergodic Probabilistic Cellular Automata

We give new sufficient ergodicity conditions for two-state probabilistic cellular automata (PCA) of any dimension and any radius. The proof of this result is based on an extended version of the duality concept. Under these assumptions, in the one dimensional case, we study some properties of the unique invariant measure and show that it is shift-mixing. Also, the decay of correlation is studied in detail. In this sense, the extended concept of duality gives exponential decay of correlation and allows to compute explicitily all the constants involved

QCD Calculations of Heavy Quarkonium States

Recent results on the QCD analysis of bound states of heavy $\bar{q}q$ quarks are reviewed, paying attention to what can be derived from the theory with a reasonable degree of rigour. We report a calculation of $\bar{b}c$ bound states; a very precise evaluation of $b, c$ quark masses from quarkonium spectrum; the NNLO evaluation of $\Upsilon\to e^+e^-$; and a discussion of power corrections. For the $b$ quark {\sl pole} mass we get, including $O(m_c^2/m_b^2)$ and $O(\alpha_s^5\log \alpha_s)$ corrections, $m_b=5.020\pm0.058 GeV$; and for the $\bar{MS}$ mass the result, correct to $O(\alpha_s^3)$, $O(m_c^2/m_b^2)$, $\bar{m}_b(\bar{m}_b)=4.286\pm0.036 GeV$. For the decay $\Upsilon\to e^+e^-$, higher corrections are too large to permit a reliable calculation, but we can predict a toponium width of $13\pm1 keV$.Comment: PlainTex file; one figur

Basic Parameters and Some Precision Tests of the Standard Model

We present a review of the masses (except for neutrino masses) and interaction strengths in the standard model. Special emphasis is put on quantities that have been determined with significantly improved precision in the last few years. In particular, a number of determinations of $\alpha_s$ and the electromagnetic coupling on the $Z$, $\alpha_{\rm QED}(M_Z^2)$ are presented and their implications for the Higgs mass discussed; the best prediction that results for this last quantity being $$M_H=102^{+54}_{-36} GeV/c^2.$$ Besides this, we also discuss a few extra precision tests of the standard model: the electron magnetic moment and dipole moment, and the muon magnetic moment.Comment: Plain TeX file. 6figure

Bound states of heavy quarks in QCD

Bound states of heavy $\bar{q}q$ quarks are reviewed within the context of QCD, paying attention to what can be derived from the theory with a reasonable degree of rigour. This is compared with the results of semiclassical arguments. Among new results, we report a very precise $O(\alpha_s^4)$ evaluation of $b, c$ quark masses from quarkonium spectrum with a potential to two loops.Comment: Plain TeX, 5 figure