Reverse Bootstrapping: IR lessons for UV physics

Abstract

S-matrix bootstrap and positivity bounds are usually viewed as constraints on low-energy theories imposed by the requirement of a standard UV completion. By considering graviton-photon scattering in the Standard Model, we argue that the low-energy theory can be used to put constraints on the UV behaviour of the gravitational scattering amplitudes.

Crossing Symmetric Spinning S-matrix Bootstrap: EFT bounds

“…We note that it seems like the denominator has a pole at ξ = 3 but this value is never attained since a < 2M 2 3 , we have ξ < 1 13. In order to obtain this numerical coefficient, we have used linear programming in Mathematica with 1700 digits of precision to find solutions to the system of inequalities (3.36) for k ≤ 21 while varying ξ in steps of 0.048 from ξ min = 0.59329 to ξ max = 2.99 and spin J from J = 0 to J max = 56.…”

“…The above exercise leads us to ξ min = 0.593 for the scalar EFT when we consider all locality constraints up to k = 21 13 This gives the following:…”

“…In recent times, there has been an increase in interest in establishing two-sided bounds on ratios of parameters in front of higher dimensional operators in the EFT lagrangians. Recent work in this direction include [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Starting from the original attempts to constrain scalar EFTs, research has been extended to external particles carrying spin [7,21,22].…”

Locality and Analyticity of the Crossing Symmetric Dispersion Relation

“…• It will be intriguing to explore our discussion in the context of spinning particles [55] as well as [56][57][58][59]. It will be worth to explore recent ideas [60][61][62][63] in the context of Feynamn block expansion.…”