ALPINIST: Axion-Like Particles In Numerous Interactions Simulated and Tabulated

Abstract

Proton beam dump experiments are among the most promising strategies to search for light and feebly interacting states such as axion-like particles (ALPs). The interpretation of these experiments is however complicated by the wide range of ALP models and the multitude of different production and decay channels that can induce observable signals. Here we propose a new approach to this problem by separating the calculation of constraints and projected sensitivities into model-independent and model-dependent parts. The former rely on extensive Monte Carlo simulations of ALP production and decays, as well as estimates of the detection efficiencies based on simplified detector geometries. Once these simulations have been performed and tabulated, the latter parts only require simple analytical rescalings that can be performed using the public code ALPINIST released together with this work. We illustrate this approach by considering several ALP models with couplings to Standard Model gauge bosons. For the case of ALPs coupled to gluons we show that the sensitivity of proton beam dump experiments can be extended significantly by considering hadronic ALP decays into three-body final states.

Feebly-interacting particles: FIPs 2020 workshop report

“…SHiP, HIKE-dump, and SHADOWS projections are based on Ref. [1451] which resums the logarithmic dependence on Λ U V through RGE evolution.…”

“…Projections: LHCb with 15 fb −1 and 300 fb −1[1003]; CODEX-b with 300 fb −1[1025]); MATHUSLA with 3 ab −1 (estimate from[1025]); FASER2 with 3 ab −1[1068]; SHiP with 2 × 10 20 pot[1402]; SHADOWS[1401] and HIKE-dump[1392] with 5 × 10 19 pot each. SHiP, HIKE-dump, and SHADOWS projections are based on Ref [1451]. which resums the logarithmic dependence on Λ U V through RGE evolution.…”

Dark sector searches at dump experiments

“…To illustrate the effect, the hypothetical reach of a forward beam-dump experiment at a 400GeV proton beam-line is illustrated in Fig. 2 using an upgraded version of the ALPINIST MC [11,12]. Curves are drawn for different levels of 'forwardness' of the initial 𝐷-meson distributions.…”

“…• ALPINIST [12] (only Axion-like particles implemented publicly at the time of writing, public meson distributions)…”

New results for searches of exotic decays with NA62 in beam-dump mode

“…With the collected statistics of (1.4 ± 0.28) × 10 17 POT, NA62 is sensitive to various decay channels (di-photon, di-lepton, hadronic) of ALPs of masses and couplings that have not yet been probed by other experiments. See the NA62 sensitivity using a toy MC [10] Fig. 8 left for photonic coupling and right for gluonic coupling.…”