The effect of the masses of the τ decay products on the transverse spin correlation in τ+τ− production at the Z pole

1996 ◽  
Vol 384 (1-4) ◽  
pp. 277-282 ◽  
Author(s):  
F. Sánchez
Keyword(s):  
Spin Correlation ◽  
Transverse Spin ◽  
Decay Products ◽  
The Masses

scholarly journals Subleading EW corrections and spin-correlation effects in $$t\bar{t}W$$ multi-lepton signatures

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Rikkert Frederix ◽  
Ioannis Tsinikos
Keyword(s):  
Phase Space ◽  
Cross Section ◽  
Top Quark ◽  
Spin Correlation ◽  
Top Quarks ◽  
Correlation Effects ◽  
Spin Correlations ◽  
Decay Products ◽  
Theoretical Predictions ◽  
The Impact

AbstractRecently a slight tension between data and predictions has been reported in $$t\bar{t}W$$ t t ¯ W production by both the CMS and ATLAS collaborations. We revisit the theoretical predictions for this process, focussing on the following two effects. We disentangle various effects that lead to asymmetries among the leptonic decay products of the (anti-)top quarks and W bosons, for which we find that the spin correlations in the top-quark pair are the dominant source. We also discuss the impact of the large, formally subleading, electroweak corrections to $$t\bar{t}W$$ t t ¯ W production at the LHC. We find that this effect changes the $$t\bar{t}W$$ t t ¯ W cross section significantly in the signature phase-space regions, and should therefore be included differentially in the theory to data comparisons.

Zero-temperature properties of quantum spin models on the triangular lattice II: the antiferromagnet

1987 ◽  
Vol 65 (1) ◽  
pp. 76-81 ◽  
Author(s):  
S. Fujiki ◽  
D. D. Betts
Keyword(s):  
Triangular Lattice ◽  
State Energy ◽  
Spin Correlation ◽  
Quantum Spin ◽  
Transverse Spin ◽  
Nearest Neighbour ◽  
Spin Correlations ◽  
Infinite Lattice ◽  
Longitudinal Correlation ◽  
Quantum Spin Models

The calculation of two- and four-spin correlations of the [Formula: see text] antiferromagnet has been extended to an N = 21 site triangular lattice. By fitting a quadratic in 1/N to the nearest neighbour transverse spin correlations, we have estimated the ground-state energy per bond on the infinite lattice to be E0/3NJ = −0.2716 ± 0.005. The nearest neighbour longitudinal correlation is estimated to be [Formula: see text]. A short-range order parameter, the chirality, is defined and estimated for the infinite lattice. From the N dependence of the three sublattice or helical magnetization, the spin correlation is conjectured to decay algebraically as [Formula: see text].

scholarly journals Measurement of the transverse spin correlation in Z → τ+ τ− decays

1997 ◽  
Vol 404 (1-2) ◽  
pp. 194-206 ◽  
Author(s):  
P. Abreu ◽  
W. Adam ◽  
T. Adye ◽  
I. Ajinenko ◽  
G.D. Alekseev ◽  
...  
Keyword(s):  
Spin Correlation ◽  
Transverse Spin

scholarly journals Bell-Type Correlation at Quantum Phase Transitions in Spin-1 Chain

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1282
Author(s):  
Dongkeun Lee ◽  
Wonmin Son
Keyword(s):  
Phase Transitions ◽  
Quantum Phase Transitions ◽  
Spin Correlation ◽  
High Order ◽  
Quantum Phase ◽  
Transverse Spin ◽  
Matrix Product ◽  
Matrix Product State ◽  
The Matrix ◽  
The One

For the identification of non-trivial quantum phase, we exploit a Bell-type correlation that is applied to the one-dimensional spin-1 XXZ chain. It is found that our generalization of bipartite Bell correlation can take a decomposed form of transverse spin correlation together with high-order terms. The formulation of the density-matrix renormalisation group is utilized to obtain the ground state of a given Hamiltonian with non-trivial phase. Subsequently Bell-type correlation is evaluated through the analysis of the matrix product state. Diverse classes of quantum phase transitions in the spin-1 model are identified precisely through the evaluation of the first and the second moments of the generalized Bell correlations. The role of high-order terms in the criticality has been identified and their physical implications for the quantum phase have been revealed.

In situ irradiation effects studies in medium- and high-voltage TEM

1995 ◽  
Vol 53 ◽  
pp. 234-235
Author(s):  
Charles W. Allen
Keyword(s):  
Cross Section ◽  
Particle Flux ◽  
Threshold Value ◽  
High Energy ◽  
Irradiation Damage ◽  
Defect Complexes ◽  
Lattice Position ◽  
Electrons And Ions ◽  
The Masses

With respect to structural consequences within a material, energetic electrons, above a threshold value of energy characteristic of a particular material, produce vacancy-interstial pairs (Frenkel pairs) by displacement of individual atoms, as illustrated for several materials in Table 1. Ion projectiles produce cascades of Frenkel pairs. Such displacement cascades result from high energy primary knock-on atoms which produce many secondary defects. These defects rearrange to form a variety of defect complexes on the time scale of tens of picoseconds following the primary displacement. A convenient measure of the extent of irradiation damage, both for electrons and ions, is the number of displacements per atom (dpa). 1 dpa means, on average, each atom in the irradiated region of material has been displaced once from its original lattice position. Displacement rate (dpa/s) is proportional to particle flux (cm-2s-1), the proportionality factor being the “displacement cross-section” σD (cm2). The cross-section σD depends mainly on the masses of target and projectile and on the kinetic energy of the projectile particle.

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