Universal limits on massless high-spin particles

Abstract

We present a model-independent argument showing that massless particles interacting with gravity in a Minkowski background space can have at most spin two. This result is proven by extending a famous theorem due to Weinberg and Witten to theories that do not possess a gauge-invariant stress-energy tensor.

The other effective fermion compositeness

“…SUSY with massless particles) and N > 8 supercharges imply the existence of massless higher-spin states which are pathological, in flat space, on very general grounds [19][20][21] (see e.g. [22] for a review).…”

“…Without any prior, our analysis above leads to 95% CL intervals of the form [−c − (g * , m − * ), c + (g * , m + * )], while our theory prior implies ]0,ĉ(g * , m * )]. Taking it into ac- 21 Initial-state photon radiation may reduce the CM energy of the dilepton production. In the LEP analyses only events with soft initial-state radiation are retained [57].…”

“…For the purpose of this analysis, we use samples of events with integrated luminosity of 3 fb −1 and increasing effective CM energy from 189 to 207 GeV. 21 We combine the limits from different energy and angular bins and obtain e R Goldstini:…”

Higher-spin fermionic gauge fields and their electromagnetic coupling

“…With this knowledge, we then move on to constructing consistent off-shell 1−s−s vertices in the following three sections. In particular, section 3 considers the massless Rarita-Schwinger field, while section 4 pertains to s = 5 2 , and section 5 generalizes the results, rather straightforwardly, to arbitrary spin, s = n + 1 2 . In section 6, we prove an interesting property of the vertices under study: an abelian 1 − s − s vertex, i.e., a 1 − s − s vertex that does not deform the original abelian gauge algebra, never deforms the gauge transformations.…”

“…Severe restrictions arise from powerful no-go theorems [1][2][3][4][5], which prohibit, in Minkowski space, minimal coupling to gravity, when the particle's spin s ≥ 5 2 , as well as to electromagnetism (EM), when s ≥ 3 2 . However, these particles may still interact through gravitational and EM multipoles.…”