Multiparticle processes and semiclassical analysis in bosonic field theories

Semiclassical description of soliton-antisoliton pair production in particle collisions

“…The reason can be traced back to the attraction between the topological soliton and antisoliton [48]: taken at rest, they accelerate towards each other and annihilate 2 into many particles. Thus, the 1 In particular, loop corrections are shown [9][10][11] to be large at g 2 NS 1. 2 We do not consider integrable models where annihilation of the soliton and antisoliton may be forbidden by conservation laws.…”

“…Indeed, the solitons can be crudely regarded [40] as bound states of N S ∝ 1/g 2 particles, where g 1 is the coupling constant. The cross section of their pair production in the collision of few particles involves the multiparticle factor [9][10][11] P few ∼ g 4N S (2N S )! ∼ exp(−const/g 2 ) due to roughly (2N S )!…”

“…An intriguing possibility of observing nonperturbative phenomena in particle collisions and in the early Universe triggered development of powerful semiclassical methods for description of false vacuum decay [1][2][3][4], instanton-like transitions [5][6][7][8] and multiparticle production [9][10][11][12][13]. Although these processes occur with exponentially small rates [14][15][16][17][18][19][20][21][22][23][24][25] in weakly interacting theories, they may be important for baryogenesis [8,26,27], stability of the Higgs vacuum [28][29][30][31][32][33][34][35], or violation of the baryon and lepton numbers at future colliders [36][37][38][39].…”

Perturbative growth of high-multiplicity W, Z and Higgs production processes at high energies

“…leading to the ultimate breakdown of the standard weakly-coupled perturbation theory, as reviewed in [8,9], see also refs. [10][11][12][13][14][15][16][17].…”

“…In particular, it was argued in the 90-s (see [8,9,[15][16][17][25][26][27] and references therein) that multi-particle production cross-sections in a scalar φ 4 -type field theory take the form: 13) in the double-scaling λ → 0, n → ∞ limit with λn and ε held fixed. This exponential behaviour of the n-particle cross-section was obtained from extrapolating results derived in perturbation theory.…”